Post by: Stormrider51 on May 05, 2011, 11:56:01 AM
I have a fairly well-equipped gunsmith shop and a number of years of experience in the shooting sports. I decided to do some testing. I took a short piece of rifled .50 cal barrel that has been laying around waiting to someday become a pistol. It was perfect for my intended use as it had never been tapped for a breech plug. I turned a brass cleaning jag down to a diameter that just would slip into the bore. The face of the jag was a very close match to the shape of the ball and came up nicely around the sides. I found a bag full of .490 balls sitting on a shelf and gathered up several thicknesses of patch material. Let me note that the balls were cast of dead-soft lead. I measured each one with micrometer calipers before use. I also used a lube made of 50/50 beeswax/vasoline that I've used for years. I decided to start with a patch thickness that would create what I consider to be a "normal" fairly tight patch/ball combo. By "normal" I mean that the PRB could be pushed through the bore smoothly using firm pressure. The section of barrel was clamped in a vise. Here's what I found.
Ball #1 measured .489". I short-started it, cut the patch at the muzzle, and pushed it through the bore. After peeling away the patch there were clearly visible impressions from the patch material around the circumference but no sign of rifling marks. Interestingly, the ball now measured .490". Had obturation already begun just from the smack I gave the short-starter and being pushed through the bore?
Ball #2 measured .490". I did everything as above except that this time I stopped short of pushing the ball all the way through. Instead, I switched ends with the ramrod and pushed it back out again. The result was almost identical to my first try. The ball showed impressions of the patch and now measured a hair over .491".
Ball #3 measured .490". Again, I did everything the same including stopping short of pushing the ball all the way through. But this time I wanted to simulate the pressure of the expanding powder gasses on the rounded base of the ball. I set the ramrod with its jag against the base of the ball and smacked it firmly with a leather mallet while pushing it back toward the muzzle. The result was that not only were there impressions of the patch material, there were also clear marks left by the rifling. More importantly, the ball now measured .492".
I intend to repeat these limited tests at least three more times to confirm my initial findings. Then I plan to repeat them using a thinner patch and a thicker one as well. The indication so far seems to indicate that a ball does "bump up" but this is where the invitation part comes in. I'd like to invite anyone who has the ability to do so to repeat these tests and report their findings in this thread. By compiling our data we can hopefully put to rest the debate over obturation.
The obvious best proof one way or the other would be to actually fire a PRB and recover it undamaged. The "undamaged" part is the kicker. Anything I can think of to fire it into will deform the front of the ball and negate the data. Someone suggested firing it into a snow bank but those are few and far between in Central Texas! If any of you folks "Up North" have access to a snow bank and the patience to try to dig a fired ball out of it....
Thanks,
John
Post by: Riley/MN on May 05, 2011, 12:05:55 PM
The other thing you could try... on a still day, shoot the ball straight up in the air and then just catch it when it comes down.....
Seriously though, I cannot imagine a soft lead round ball not bumping up - but I guess I have never been challenged on that before.
I will be watching this thread.....
Post by: Gordon H.Kemp on May 05, 2011, 01:50:41 PM
But , whats our opinion compared to the many great and glorious "Poobahas" that seem to be accepted as the last word in all things muzzleloading .
Keep us posted on any updates , and THANKS !
Post by: Swamp on May 05, 2011, 02:22:48 PM
Quote
The other was that I didn't want to be a part of any forum where a few members were allowed to dominate discussions and, even worse, be rude in their replies. (I witnessed several newcomers being treated in an insulting manner.)
Stormrider, you have stumbled on the right place to be! You will not get that kinda response here I assure you. So now you have seen how others run their places, so why don't you just stick around right here, and be a part of the best traditional muzzleloading organization there is, the TMA!
Welcome my friend!
Post by: Loyalist Dave on May 05, 2011, 03:26:31 PM
Second, the ball may not be "smacked" by the gasses as you suppose..., it is possible hit by the top of the powder column (which is softer than lead), which compresses as the powder column deflagrates. This then may overcome a portion of the inertia and friction of the patched round ball, to start the ball moving forward, before the full powder column ignites and becomes gas, pushing against the patched round ball. OR..., it might fully deflagrate before the ball really begins moving..., thus making your premise valid. It needs testing.
Your test showed that using a short starter the ball is deformed several thousandths of an inch, but not all of us use short starters. Some have coned barrels, some use patch and ball combinations that are started by their thumbs, and some like me simply force the ball with a push, not a smack. I also stop when the ball is steated, and don't bounce the ramrod on top of the loaded ball as some folks like to do. I know such an action deforms the ball, and I try to avoid it.
To actually test, you need to fire the projectile into ballistic gellatin, which is used to recover any type of bullet (even pure lead) for ballistic comparisons. Once recovered the bullet may be measured to see if it actually obturated, or if it simply deformed, and how much it deformed.
However, I think that since most of us have recovered fired patching material uncut by the rifling, when shooting on the range, that's pretty conclusive proof that the ball doesn't "obturate" for it should cut through the patching material if the ball was sealing the bore.
LD
Post by: Stormrider51 on May 05, 2011, 04:01:09 PM
Quote from: "Riley/MN"
HA, Pitchy might have some from that snowbank he shoots inta (if it has thawed yet)
The other thing you could try... on a still day, shoot the ball straight up in the air and then just catch it when it comes down.....
Seriously though, I cannot imagine a soft lead round ball not bumping up - but I guess I have never been challenged on that before.
I will be watching this thread.....
Riley...Tell you what, you come and catch the ball as it comes down. Your eyes are probably better than mine and I'll loan you my old catchers mit. You do that and I'll give you a cold mug or two of homebrewed beer.
John
Post by: Stormrider51 on May 05, 2011, 04:03:32 PM
Quote from: "Gordon H.Kemp"
Stormrider51 , I think I know the site of wich you speak , and yes , there are several self proclaimed "Experts" that assume they have all the answers to all questions . I like the tests that you tried , and believe it shows that those of us that accept soft lead obturates when normal ignition preasures are applied to overcome the friction of the rule that an object at rest, tends to stay at rest Etc. I think that if you repeat the same test proceedure with a thinner patch there will be a tad more obtuation (tapping it with the mallet) than with the tighter patch because there will be less resistance to the obtuation of the ball . Its my opinion that the ball can only obtuate to the actual measurement of the bore , but that it WILL obtuate .
But , whats our opinion compared to the many great and glorious "Poobahas" that seem to be accepted as the last word in all things muzzleloading .
Keep us posted on any updates , and THANKS !
Gordon,
Thanks for the encouragement.
John
Post by: Stormrider51 on May 05, 2011, 04:06:49 PM
Quote from: "Swamp"
QuoteThe other was that I didn't want to be a part of any forum where a few members were allowed to dominate discussions and, even worse, be rude in their replies. (I witnessed several newcomers being treated in an insulting manner.)
Stormrider, you have stumbled on the right place to be! You will not get that kinda response here I assure you. So now you have seen how others run their places, so why don't you just stick around right here, and be a part of the best traditional muzzleloading organization there is, the TMA!
Welcome my friend!
Swamp,
I've been reading on here for a few days and haven't seen anyone "flame" anybody else yet. There's no point in it and when done to newcomers is just plain sad. One guy over there reminds me of a chihuahua, always looking for someone to bark at.
John
Post by: Stormrider51 on May 05, 2011, 04:39:05 PM
Quote from: "Loyalist Dave"
First, let me point out that "obturation" does not mean a mere deformation of the bullet, but means "the process of a bullet or pellet, made of soft material and often with a concave base, flaring under the pressure of firing to seal the bore and engage the barrel's rifling." Your tests noted that the ball was deformed, but a .492 ball isn't sealing a .500 bore right?
Second, the ball may not be "smacked" by the gasses as you suppose..., it is possible hit by the top of the powder column (which is softer than lead), which compresses as the powder column deflagrates. This then may overcome a portion of the inertia and friction of the patched round ball, to start the ball moving forward, before the full powder column ignites and becomes gas, pushing against the patched round ball. OR..., it might fully deflagrate before the ball really begins moving..., thus making your premise valid. It needs testing.
Your test showed that using a short starter the ball is deformed several thousandths of an inch, but not all of us use short starters. Some have coned barrels, some use patch and ball combinations that are started by their thumbs, and some like me simply force the ball with a push, not a smack. I also stop when the ball is steated, and don't bounce the ramrod on top of the loaded ball as some folks like to do. I know such an action deforms the ball, and I try to avoid it.
To actually test, you need to fire the projectile into ballistic gellatin, which is used to recover any type of bullet (even pure lead) for ballistic comparisons. Once recovered the bullet may be measured to see if it actually obturated, or if it simply deformed, and how much it deformed.
However, I think that since most of us have recovered fired patching material uncut by the rifling, when shooting on the range, that's pretty conclusive proof that the ball doesn't "obturate" for it should cut through the patching material if the ball was sealing the bore.
LD
Dave,
Very good points and yes, I was using the wrong term for what I'm talking about. Using "upset", "shorten", or "deform" would have been more accurate as the ball itself never touches the rifling in a normal load. My question was whether or not the ball grows larger in diameter thereby compressing the patch material and helping to seal the bore. It is my opinion, and opinion is the lowest form of knowledge, that it can't help but do so given the softness of pure lead and the laws of physics. I'm looking for ways to test the theory and hopefully others to repeat the tests for verification. Interested?
As for ballistic gelatin, I've used it to test the expansion of hollowpoint pistol bullets in the past and on one occasion even fired a lead ball into it for a comparison. The pure lead ball mushroomed beautifully which would prevent an accurate determination of how much deformation was due to which factor.
John
Post by: sse on May 05, 2011, 05:39:07 PM
Quote
Riley...Tell you what, you come and catch the ball as it comes down.
Post by: Riley/MN on May 05, 2011, 05:44:28 PM
Quote from: "Stormrider51"
Riley...Tell you what, you come and catch the ball as it comes down. Your eyes are probably better than mine and I'll loan you my old catchers mit. You do that and I'll give you a cold mug or two of homebrewed beer.
John
Ummm, I think I have a meeting tonight...
Post by: Loyalist Dave on May 06, 2011, 08:01:36 AM
Quote
My question was whether or not the ball grows larger in diameter thereby compressing the patch material and helping to seal the bore.
I think that's already been demonstrated by you. It would deform and thus "tighten" the fit in most loadings. Even if you didn't use the short starter, the ball does get some sort of sharp smack when it's launched, right? There would be some "squashing" of the ball as it moves forward, from the powder blast. You might see how tough it is to load a .495 ball vs. the same patching material and a .498 ball (Lee makes a mold). If it's tighter than you can really handle, with a .003 difference, I think you can conclude it does seal the bore better than a human can.
As for the gelatin, you don't need to fire a full load, and you may need to check the gelatin mixture. We wouldn't need to test for ballistic performance, just recover the projectile, so a softer mix would work. For example, if you fired a 20 grain load instead of 60 or higher, you might have less expansion, but after all if 20 grains expands the ball by x amount, then 40 should to more, and 60 even more.
It's also possible that a 20 grain load will give you all the expansion you will ever get (lets not forget the rifled pistols of the period eh?), as perhaps after the first 20 grains go boom..., the ball is moving forward thus not giving enough inertia to cause further expansion..., and the remainder of the load of say a 60 grain load, merely adds velocity?
We'd need soft gelatin, and some really good shots, and hit the gelatin at say 100 yards..., thus allowing the ball to decelerate some, so we could compare. If the ball from a 20 grain load isn't deformed more than from a 40 or 60 grain load, you'd know it does seal, it works with a pistol load, and the remaineder of the load accelerates the ball.
I have also heard of firing a projectile upward at an angle into a silk handkerchief..., which supposedly will get caught and ride along with the bullet, and allow you to recover it..., but this was supposedly with revolver rounds, so again use a light load.
LD
Post by: Two Steps on May 06, 2011, 10:08:03 AM
Al
Post by: Gordon H.Kemp on May 06, 2011, 12:12:33 PM
So just ignore the discussions such as this subject and enjoy the hobby for what it is . If at some point in your journey a question you would like answered arises , please ask , and there will be folks that will have the answers on this site . We all started not knowing many things and had to learn as we progressed . Your questions will be treated with respect , and answered in a cival manner.
Post by: Stormrider51 on May 06, 2011, 03:13:07 PM
Quote from: "Loyalist Dave"
QuoteMy question was whether or not the ball grows larger in diameter thereby compressing the patch material and helping to seal the bore.
I think that's already been demonstrated by you. It would deform and thus "tighten" the fit in most loadings. Even if you didn't use the short starter, the ball does get some sort of sharp smack when it's launched, right? There would be some "squashing" of the ball as it moves forward, from the powder blast. You might see how tough it is to load a .495 ball vs. the same patching material and a .498 ball (Lee makes a mold). If it's tighter than you can really handle, with a .003 difference, I think you can conclude it does seal the bore better than a human can.
As for the gelatin, you don't need to fire a full load, and you may need to check the gelatin mixture. We wouldn't need to test for ballistic performance, just recover the projectile, so a softer mix would work. For example, if you fired a 20 grain load instead of 60 or higher, you might have less expansion, but after all if 20 grains expands the ball by x amount, then 40 should to more, and 60 even more.
It's also possible that a 20 grain load will give you all the expansion you will ever get (lets not forget the rifled pistols of the period eh?), as perhaps after the first 20 grains go boom..., the ball is moving forward thus not giving enough inertia to cause further expansion..., and the remainder of the load of say a 60 grain load, merely adds velocity?
We'd need soft gelatin, and some really good shots, and hit the gelatin at say 100 yards..., thus allowing the ball to decelerate some, so we could compare. If the ball from a 20 grain load isn't deformed more than from a 40 or 60 grain load, you'd know it does seal, it works with a pistol load, and the remaineder of the load accelerates the ball.
I have also heard of firing a projectile upward at an angle into a silk handkerchief..., which supposedly will get caught and ride along with the bullet, and allow you to recover it..., but this was supposedly with revolver rounds, so again use a light load.
LD
Dave,
I like the way you think. Thanks for the insight and suggestions.
John
Post by: Stormrider51 on May 06, 2011, 03:15:33 PM
Quote from: "Two Steps"
What about water? Large stock tank...swimming pool...my front yard after a rain
Al
Al,
I appreciate the idea but water is less "soft" than you might think. It doesn't compress at all which would cause the ball to deform.
Thanks,
John
Post by: Stormrider51 on May 06, 2011, 03:39:50 PM
Quote from: "Gordon H.Kemp"
I"d like to add at this time , for those who may just starting their journey into the addiction of muzzleloading and the history that surround these weapons , that wether or not a soft lead spehre obtuates is not relative to enjoying this hobby . Its just another fascet of the hobby that some wish to pursue .
So just ignore the discussions such as this subject and enjoy the hobby for what it is . If at some point in your journey a question you would like answered arises , please ask , and there will be folks that will have the answers on this site . We all started not knowing many things and had to learn as we progressed . Your questions will be treated with respect , and answered in a cival manner.
Gordon,
What you say is very true. All of the shooting sports have many facets and traditional muzzleloading has more than many of the others. Some are deeply into the history with some going far enough to want to re-create it in detail. Some love creating functional works of art be it a gun, powder horn, pouch, or whatever. Some just want to go shoot. It was the technical side of shooting and ballistics that led me to become a gunsmith in the first place. I can't get my hands on a gun without wanting to learn how to wring every bit of accuracy possible out of it. Not only that, I want to understand why it is accurate (or inaccurate).
Having said all that, let me add that if you feel I'm heading off into an area that doesn't fit the intent of the forum please tell me so. I'm on the forum because, for the first time in many years, I have the time to experiment. Just thought I'd see what others have found to be true.
Thanks,
John
Post by: Gordon H.Kemp on May 06, 2011, 04:21:39 PM
Post by: Swamp on May 06, 2011, 08:45:29 PM
Post by: Gordon H.Kemp on May 06, 2011, 09:46:18 PM
Post by: Stormrider51 on May 06, 2011, 09:51:26 PM
I did take the time to clamp the barrel section in a vise and experiment with thinner patches. The results were interesting. This patch/ball combo started easily with the short starter and could be pushed through the bore with light pressure on the ramrod/jag. I did exactly the same sequence as previously but the results were very different. The measured diameter of the balls before testing ran between .489 and .490. None of the balls measurably increased in diameter at any stage in the experiment. I even went back and repeated the test where I smacked the ramrod from the rear but used a stronger blow. This time the ball actually popped out of the barrel and I had to go borrow a pillow from the bedroom to act as a catchers mit. The result was that the balls did not show more than a light imprint from the patch and no measurable increase in diameter. It would seem that an increase in diameter does depend on the initial inertia and friction. Of course, I didn't actually set off a charge of black powder. Still working on how to accomplish that. The ideal would be a high-speed camera that could take a photo of the ball shortly after it sheds its patch. I don't have that kind of money.
Next is to try a really tight patch.
John
Post by: Stormrider51 on May 08, 2011, 04:54:13 PM
Today I took some thicker patching and repeated my earlier tests. This time the balls were just plain hard to start into the muzzle and required serious effort to push down the bore. Even when pushed straight through, there were definite impressions left in the ball from the rifling. A .490" ball measured a hair UNDER .490" at the points where the lands left their marks. This would seem to indicate that the thicker patch compressed the lead. As best I could measure the diameter in the grooves increased slightly, which makes sense. In both cases, land and groove, the difference was visible on the micrometer caliper but not enough to give a definite amount. My much more accurate digital micrometers are too thick in the stem to be used.
The push it in and push it out test gave similar results except that I was able to measure an average increase in groove diameter of .002". The land diameter remained just under the original .490".
When I did the "whack it will a mallet" test things got interesting. I ran the PRB down, smacked the rod firmly with the mallet, and then pushed the ball back out. It took a LOT of effort to push it back out. This time the patch had clear cuts from the rifling in it all the way around. Groove diameter had increased .004" over its original size while land diameter remained a hair under original diameter.
Well, it's Mother's Day and I have just been informed that my presence is required elsewhere. I'll come back later today and tomorrow to do a summary.
Take care,
John
Post by: Gordon H.Kemp on May 08, 2011, 11:42:31 PM
Post by: Captchee on May 09, 2011, 11:14:15 AM
Stormrider51 , welcome to the TMA . I think you will find that things are much different here then in other places . While you may find disagreements , those disagreements WILL be done in an adult manor and with respect . We simply do not allow what so many other places allow .
As to your subject .
I would also agree with Dave’s points but in this case and most times for these type of discussions , its understood that obturation of RB is the expansion or deformation caused by ignition
There has for a very long time been this division of opinion as to if a RB actually obturate’s or not ..
On one side you have those who feel that a ball starts moving before pressure builds to the point that it can expand the ball
Then on the other you have those that believe the resistance of the ball itself is the key to the expansion. .
As to the first . This is I believe based on the theory that the ball is part if the total load , there for it isn’t hit by pressure but accelerated by the pressure . As such they poo poo the tests that fedela and others did concern short starting barrels . Which as mention documented obturation happening .
However we should understand that in those tests , the reason for that obturation was indeed the effect of a pressure wave hitting the ball . Not the result of the ball traveling on the leading edge of that pressure wave .
Thus IMO , their reason is understandable , but for the fact that it doesn’t take into account resistance of the projectile , nor does it account for the resistance of the opposing air pressure while the ball travels on that pressure wave .
The problem in disproving or proving the theory is that regardless of what you shoot into the projectile is going to encounter resistance . That resistance is going to expand the ball and thus yield inaccurate results . Especially concerning ballistics jell . Even water is going to provide a given amount of resistance . As such your most likely still going to see a .002+ expansion.
Many years ago I read an article where a fella was trying to prove the theory by placing a paper target in front of the muzzle , just out of the muzzle blast area . . He then measured the resulting hole.
Supposedly this showed that indeed the ball had expanded.
Problem was , folks suspected that the patch had not yet separated . Thus creating the larger hole . So he again tested his theory at a longer distance . The results still showed a larger projectile then was loaded . But could this have been a natural result from air resistance or was it a result of his loading ????/
Your results as of yet , are showing deformation by loading , not really obturation cased by the ignition process .
Myself I don’t see how you will be able to physically , accurately prove the theory without having a long enough barrel to contain the projectile to its outer limit of its movement .As such I think we must resort to math and physics to prove obturation.
Remington as I recall actually did this back in the 40’s . not on only did they do it mathematically but also physically.
If we accept that lead is a physical plastic and get over the idea that a projectile is a solid , just because it feels hard . We then can understand that there is a given point where all materials , when subject to pressure , begin to act like liquids, even though they may remain somewhat solid . If we understand that ,then we can understand that when the pressure exerted against it reaches the plastic deformation “ all materials have this point , “the ball then will expand.
Remember in school they taught us that for every reaction , there is an equal and opposite reaction . With plastic deformation , while its given that plastic deformation irreversible an object in the plastic deformation range will first have undergone elastic deformation, which is reversible, so the object will return part way to its original shape. IE, equal and opposite reaction
think of a rubber ball . But with lead the plastic deformation is greater then its Elastic deformation is less . But that has not change the fact that it has or will expand even greater . Physics say its has to .
Again Remington proved this long ago . Even today with cased bullets , slow motion x-ray photos show the bullets expanding within the bore . Those same photos show an even greater increase in the center of the body when viewed after leaving the bore and at the targets.
This is caused by the resistance of the bullet traveling through air . IE weight encountering drag at velocity and thus the effects of the projectiles plastic deformation value ..
IE the forces on the front of the projectile are causing that section of the projectile to encounter drag . while the back section of the projectile isn’t encountering the same amount of drag . as such the back is trying to push past and through the front , thus causing the projectile to expand in the center . This effect increases when the front comes in contact with even more resistance . IE a target .
A good example of this is a big lead conical after mushrooming from hitting a target . Often times you can still clearly see the base . But the forward section is enlarged . This enlargement isn’t the front being forced out . it’s the center of the projectile expanding out and around the front of the projectile which contacted the resistant first .. As the total mass slows to a stop , it leaves the back end of the projectile setting center of the mass . Again Physics
So once we understand the dynamics of whats going on . We then have to accept the fact that a RB upon ignition has to expand within the bore even if from nothing else then the effects of acceleration on it physical properties . The faster that acceleration , the greater the expansion .
Anyways , sorry to be so long winded . Its a very interesting subject that has been proven time and time again . Both in actual application and scientifically .
Of course there will always be those who don’t believe it . Thus we will always have the fun of proving it over and over again .
Post by: Stormrider51 on May 09, 2011, 11:43:14 AM
Quote from: "Gordon H.Kemp"
For what its worth , some years ago Ed Yard performed a series of tests to record BP preasures with different powde loads and components ,patch lube , patch material and projectile weight s and dia . The barrels were made and furnished by GM . There was also a series of tests performed by Sam Fadala to demonstrate how short started projectile cause barrel bulgeing and rupturing , I believe he used copper tubing it made the failure points quite visable. These tests also indicated round ball obturation all though that wasn>t the prime purpose of the tests . Also Bill knight wrote of maany tests of BP and the effects from heat , cold moisture etc. I believe I have the test results amoungest my not so carefully organized files if you don"t have access to them . I"m also quite certain that Ductch Schultz mentions obtuation in his accuracy papers . looking forward to further testing .
Gordon,
I would appreciate seeing your notes if it's not too much trouble or if you could point me toward a website where they are published. I have Dutch's papers somewhere in my also not too carefully organized files. I seem to remember that he mentioned obturation in relation to inertia and resistance. I'm done for now with my tests, inadequate as they were. I'll be writing a synopsis in a little while. Hopefully, some newcomer to the sport may find them interesting.
Thanks,
John
Post by: Stormrider51 on May 09, 2011, 11:46:21 AM
Quote from: "Captchee"
Good morning fellas
Stormrider51 , welcome to the TMA . I think you will find that things are much different here then in other places . While you may find disagreements , those disagreements WILL be done in an adult manor and with respect . We simply do not allow what so many other places allow .
As to your subject .
I would also agree with Dave’s points but in this case and most times for these type of discussions , its understood that obturation of RB is the expansion or deformation caused by ignition
There has for a very long time been this division of opinion as to if a RB actually obturate’s or not ..
On one side you have those who feel that a ball starts moving before pressure builds to the point that it can expand the ball
Then on the other you have those that believe the resistance of the ball itself is the key to the expansion. .
As to the first . This is I believe based on the theory that the ball is part if the total load , there for it isn’t hit by pressure but accelerated by the pressure . As such they poo poo the tests that fedela and others did concern short starting barrels . Which as mention documented obturation happening .
However we should understand that in those tests , the reason for that obturation was indeed the effect of a pressure wave hitting the ball . Not the result of the ball traveling on the leading edge of that pressure wave .
Thus IMO , their reason is understandable , but for the fact that it doesn’t take into account resistance of the projectile , nor does it account for the resistance of the opposing air pressure while the ball travels on that pressure wave .
The problem in disproving or proving the theory is that regardless of what you shoot into the projectile is going to encounter resistance . That resistance is going to expand the ball and thus yield inaccurate results . Especially concerning ballistics jell . Even water is going to provide a given amount of resistance . As such your most likely still going to see a .002+ expansion.
Many years ago I read an article where a fella was trying to prove the theory by placing a paper target in front of the muzzle , just out of the muzzle blast area . . He then measured the resulting hole.
Supposedly this showed that indeed the ball had expanded.
Problem was , folks suspected that the patch had not yet separated . Thus creating the larger hole . So he again tested his theory at a longer distance . The results still showed a larger projectile then was loaded . But could this have been a natural result from air resistance or was it a result of his loading ????/
Your results as of yet , are showing deformation by loading , not really obturation cased by the ignition process .
Myself I don’t see how you will be able to physically , accurately prove the theory without having a long enough barrel to contain the projectile to its outer limit of its movement .As such I think we must resort to math and physics to prove obturation.
Remington as I recall actually did this back in the 40’s . not on only did they do it mathematically but also physically.
If we accept that lead is a physical plastic and get over the idea that a projectile is a solid , just because it feels hard . We then can understand that there is a given point where all materials , when subject to pressure , begin to act like liquids, even though they may remain somewhat solid . If we understand that ,then we can understand that when the pressure exerted against it reaches the plastic deformation “ all materials have this point , “the ball then will expand.
Remember in school they taught us that for every reaction , there is an equal and opposite reaction . With plastic deformation , while its given that plastic deformation irreversible an object in the plastic deformation range will first have undergone elastic deformation, which is reversible, so the object will return part way to its original shape. IE, equal and opposite reaction
think of a rubber ball . But with lead the plastic deformation is greater then its Elastic deformation is less . But that has not change the fact that it has or will expand even greater . Physics say its has to .
Again Remington proved this long ago . Even today with cased bullets , slow motion x-ray photos show the bullets expanding within the bore . Those same photos show an even greater increase in the center of the body when viewed after leaving the bore and at the targets.
This is caused by the resistance of the bullet traveling through air . IE weight encountering drag at velocity and thus the effects of the projectiles plastic deformation value ..
IE the forces on the front of the projectile are causing that section of the projectile to encounter drag . while the back section of the projectile isn’t encountering the same amount of drag . as such the back is trying to push past and through the front , thus causing the projectile to expand in the center . This effect increases when the front comes in contact with even more resistance . IE a target .
A good example of this is a big lead conical after mushrooming from hitting a target . Often times you can still clearly see the base . But the forward section is enlarged . This enlargement isn’t the front being forced out . it’s the center of the projectile expanding out and around the front of the projectile which contacted the resistant first .. As the total mass slows to a stop , it leaves the back end of the projectile setting center of the mass . Again Physics
So once we understand the dynamics of whats going on . We then have to accept the fact that a RB upon ignition has to expand within the bore even if from nothing else then the effects of acceleration on it physical properties . The faster that acceleration , the greater the expansion .
Anyways , sorry to be so long winded . Its a very interesting subject that has been proven time and time again . Both in actual application and scientifically .
Of course there will always be those who don’t believe it . Thus we will always have the fun of proving it over and over again .
Charles,
Thank you for the information. And yes, I like this forum. It's a welcome change from that other one.
Take care,
John
Post by: Double Barrel on May 09, 2011, 12:06:59 PM
Post by: Stormrider51 on May 09, 2011, 12:51:33 PM
The thin patch test I did was intended to specifically address the situation of being able to start a PRB with thumb pressure (in an un-coned muzzle). Doing so is obviously possible and PRB was pushed easily down the bore and back out. So easily that when I smacked the rod with a mallet the ball flew completely out of the barrel and showed neglegible increase in diameter. It's hard to believe that pressure from the exploding powder would have time to act on the ball before it was expelled from the barrel. This would result in the classic "burned patch" when recovered after firing and the resultant poor accuracy normally observed in such situations.
Testing with what I consider to be normal patch thickness revealed what I expected to see. I was able to start the PRB with a light smack of my palm on the short starter and then was able to push it down the bore with firm steady pressure. The final results indicated that the ball did indeed upset and increase in diameter which would aid in compressing the patch as noted above. This is the sort of patch/ball combo that has always given me the greatest accuracy in my rifles.
The results of the thick patch testing were surprising to me while also providing the most compelling evidence of ball upset. In the past, when I would recover a fired patch that showed cuts from the rifling around the circumference of the ball, I assumed that the cuts happened as the ball was shoved down the bore on loading. It seemed to make sense as the ball would be pushing and stretching the material on the way down the bore. In the thick patch test however, a PRB pushed straight through didn't show patch cutting even though I was just short not being able to get the PRB to move without resorting to the "pile driver" pounding I've seen some shooters use. It didn't show patch cutting when pushed back out either. But when I smacked the rod with a mallet before pushing the ball back up the bore there were cuts that looked like what I'd see from a overly tight patch/ball on recovering a fired patch.
Again, my tests were admittedly limited and would need to be repeated several times to verify accuracy. Having them repeated by someone other than me would be ideal. The greatest weakness in my methods is that I can't figure out a way to actually fire a ball and recover it undamaged. High-speed photography might well reveal a shortened ball on shedding the patch but that is beyond my wallet as well.
Take care,
John
Post by: Captchee on May 09, 2011, 03:39:33 PM
again even a lose fitting ball will expand .
you can never get the acceleration needed to produce the effect because physically by striking your RR you not even beginning to replicate the force of acceleration obtained by the explosion.
In fact what your doing is getting expansion by force striking an object , not by propelling and object
Lets see if I can explain this better .
Lets assume that the ball rides the pressure wave . IE nothing is striking the ball , its accelerating .
Lets say a given test load produces 1700 ft per second
1 mile =5280ft
IE its traveling 1 mile in 3.10 sec
60 sec per minute =19.35 miles per min.
60 min. per hour =1161mph
Now lets think of the G’s that imparts onto an object if it goes from 0 to 1161 mph in 1 /100000th of a sec ?
Even if we accept slower burn , its still accelerated to that speed , in less the 28 inches .
The force of that acceleration alone will cause expansion even with no expansion taking place by the propelling force at all .
Post by: Gordon H.Kemp on May 09, 2011, 04:26:55 PM
There has been one factor left out of the test results and that is the added resistance of the ball patch combo being forced against the spiral of the lands to begin rotation .
Now this brings up another question ? We need to repeat these tests on how much obturation takes place in a smoothbore . ???
I don"t know if its still available on the TMA archives but the last reports on BP behavior may be able to be pulled up . Bill Knight no doubt , has forgotten more about BP then most of us will ever know . I will copy off the tests by Ed Yard and Fadala and post them . It will take a while as I know less about computers then flying the space shuttle.
Post by: Stormrider51 on May 09, 2011, 06:59:59 PM
Quote from: "Captchee"
Stormride
again even a lose fitting ball will expand .
you can never get the acceleration needed to produce the effect because physically by striking your RR you not even beginning to replicate the force of acceleration obtained by the explosion.
In fact what your doing is getting expansion by force striking an object , not by propelling and object
Lets see if I can explain this better .
Lets assume that the ball rides the pressure wave . IE nothing is striking the ball , its accelerating .
Lets say a given test load produces 1700 ft per second
1 mile =5280ft
IE its traveling 1 mile in 3.10 sec
60 sec per minute =19.35 miles per min.
60 min. per hour =1161mph
Now lets think of the G’s that imparts onto an object if it goes from 0 to 1161 mph in 1 /100000th of a sec ?
Even if we accept slower burn , its still accelerated to that speed , in less the 28 inches .
The force of that acceleration alone will cause expansion even with no expansion taking place by the propelling force at all .
Amen to everything you said. Plus, I think that since I was able to measure bullet upset with many hundreds times less pressure than what exists in a barrel during actual firing situations, there can't be much doubt that it does happen. I think the data also shows that the greatest upset will happen when there is sufficient tightness to cause friction resistance.
John
Post by: Stormrider51 on May 09, 2011, 07:02:49 PM
Quote from: "Gordon H.Kemp"
Stormrider51 at this point it seems all evidence , both mathamatically and pysica indicate that obturation is a fact and not just a theory , and so far no one has come forward with evidence to disprove these findings .
There has been one factor left out of the test results and that is the added resistance of the ball patch combo being forced against the spiral of the lands to begin rotation .
Now this brings up another question ? We need to repeat these tests on how much obturation takes place in a smoothbore . ???
I don"t know if its still available on the TMA archives but the last reports on BP behavior may be able to be pulled up . Bill Knight no doubt , has forgotten more about BP then most of us will ever know . I will copy off the tests by Ed Yard and Fadala and post them . It will take a while as I know less about computers then flying the space shuttle.
Interesting that you should mention smoothbores. You were spying and know that I got one in the mail today, right? Anybody got a section of cut-off smoothie barrel?
John
Post by: R.M. on May 09, 2011, 07:11:59 PM
Post by: Stormrider51 on May 09, 2011, 07:58:36 PM
Quote from: "R.M."
John, you could always lop off a couple of inches from that new gun.
Hmmmmmm......let me think about that for a moment....................................Nope.
Post by: FlintSteel on June 08, 2011, 10:23:41 AM
Quote from: "Stormrider51"
Maybe I watch too much TV. But on shows like NCIS and CSI they are always firing into a tank that they recover pristine bullets undeformed to compare rifleing marks. I also remember a show that was about the arsenal in Alabama where they refit and recondition weapons for the military that they fire into a tank and recover bullets.Quote from: "Two Steps"What about water? Large stock tank...swimming pool...my front yard after a rain
Al
Al,
I appreciate the idea but water is less "soft" than you might think. It doesn't compress at all which would cause the ball to deform.
Thanks,
John
Dunno.
Post by: Riley/MN on June 08, 2011, 11:21:09 AM
Quote from: "FlintSteel"
Maybe I watch too much TV. But on shows like NCIS and CSI they are always firing into a tank that they recover pristine bullets undeformed to compare rifleing marks. I also remember a show that was about the arsenal in Alabama where they refit and recondition weapons for the military that they fire into a tank and recover bullets.
Dunno.
I am guessing that those bullets are NOT pure lead....
Post by: Stormrider51 on June 08, 2011, 11:45:26 AM
John
Post by: Rasch Chronicles on August 12, 2011, 01:18:34 AM
I would guess if something blows up behind you, your behind starts to move before the front, causeing everything to pile up before the front gets a going! I wouldn't be surprised if a roundball becomes squished front to back.
Best Regards,
Albert A Rasch
The Rasch Outdoor Chronicles™ (http://http)
Beekeeping- Just Not by Design… (http://http)
Post by: Stormrider51 on August 12, 2011, 10:15:36 AM
Hope you are keeping your head down over there in "Stan". I've continued to do a little experimentation from time to time on ball expansion or upset. It's too hot here in Texas to do much outside so I hide out in my shop. I cast some balls from wheel weights and included them in the tests as a comparison to pure lead. I also tried different thicknesses of patch material. Here's something that I thought was interesting. When I pushed a really tight patch/ball (pure lead) combo completely through a barrel section and then measured the ball with a micrometer, I found an average .003" decrease in size front to rear and a visible flattening of the sprue area. Did it come from the whack with my hand on the short starter, the pressure of me pushing the ball through the barrel, or both? Regardless, the impression of the patch material where the rifling pressed it into the ball were very visible although I couldn't detect any increase in diameter. If we are flattening the front of the ball on loading and it is humping up from the rear on firing then were aren't really firing a "round" ball downrange. It would look more like a pumpkin. The same test using a hard wheel weight ball didn't produce the same degree of flattening and I'd have to squint reall hard to read a difference on the mic. Is that good or bad? I don't know. I need to take some pure lead balls and some wheel weight balls to the range and fire them for group at 100 yards because accuracy is what it's all about.
Storm
Post by: Rasch Chronicles on August 12, 2011, 11:14:16 AM
I think that will be very interesting. I don't know much about shooting blackpowder per se, but it seems that the overwhelming consensus is that you need soft lead, thick patches (within reason), and tight fit, to get a ball to be accurate. Without soft (pure) lead, the ball won't deform into the rifleing and the patch won't be as effective a seal.
I had asked a similar question elsewhere because I wanted to build a 36cal Tennessee rifle as an all round game rifle. What I did not realize was that a 358 ball only weighs 68gr! I have 22 rimfire with bullets that heavy! Anyway before I came to that realization, I didn't undrstand why a 358 ball was considered marginal on deer. I assumed that it was something to do with the pure lead, so I asked about wheel weight lead, knowing it could be heat treated and hardened. So that's where my search started.
The long and the short of it is that I have now decided I will need to build two Tennessee rifles, one in 32, and the other in 50.
Best regards,
Albert “Afghanus” Rasch
The Rasch Outdoor Chronicles™ (http://http) Darn Tough Vermont: The Best Socks! (http://http)
Post by: Stormrider51 on August 12, 2011, 03:34:46 PM
You can never have too many. On the other hand, do you need two calibers in the same style of rifle or could you have two styles in about the same caliber or maybe a rifle and a smoothbore? I'm just tossing this out as a thought. I may step on some toes here and if I do I'm sorry but opinions on minimum caliber necessary for deer sized game have changed a lot since 1959 when I first hunted with a longrifle. My first rifle was a .40 and the deer I shot didn't seem to think that .390 was too small a ball. I have to add that I was 8 years old, my father was God, and he taught me to pass on any shot where I wasn't absolutely sure of shot placement. I didn't have a lot of choice since he was usually sitting right beside me in the deer stand. Hunting distances in the Texas Hill Country tend to be fairly short anyway. I passed on a lot more shots than I took. I still do, come to think of it. Anyway, back then most members of the now long defunct Powder Horn Club here in Austin were shooting originals or hand built reproductions based on original Pennsylvania rifles. Plains style rifles like the Hawken hadn't come into vogue and the average caliber was forty-something. Anybody who showed up with a .50 was toting a monster and could expect some good natured ribbing. So what changed? Nowadays I read that a .50 is very minimal when it comes to a serious hunting rifle. Really? Why? I don't know. Given that bit of info I'm surprised that the Colonists didn't starve to death when everything they shot ran away. Did they limit themselves to squirrels, rabbits, and turkeys? So what's with all the stories about killing bears?
I spent most of my adult life working as a paramedic. One of the deadest of the DRT (dead right there) men I ever saw had been shot by his 8 year old nephew with a tiny .25 acp pistol that the kid mistook for a cigarette lighter. The .25 acp is often referred to as a "mouse gun" and I'll admit it wouldn't be my first choice as a defensive pistol but this shot blew through the sternum and punctured the aorta, the main artery rising from the heart. It was sort of like blowing out a tire. The patient was dead despite our best efforts to save his life. It wasn't the caliber, it was the placement. I also worked an attempted suicide where the patient shot himself through a lobe of his right lung with a .44 Magnum. He was still conscious and talking to us as we wheeled him into the ER and he survived the incident although minus a piece of his lung. I doubt that anyone would call a .44 Mag underpowered but even so it didn't do the job the shooter desired in this case. It's all about accuracy and shot placement.
I'm not saying that you shouldn't get a .32 and a .50 in the same style if that's what you want, just that I hunted everything from squirrels and rabbits to hogs and deer with a .45 caliber for a very long time. Maybe a rifle and a smoothbore? Then you could add birds to the list. Just sayin'.
Storm