More on the Ante-Chamber

[Uncle Russ]

This is for information stating what I found on my barrel today.
I have never heard, or read, of an incident with a Green Mountain Barrel, so what I'm reporting may be old hat to may of our shooters.
Others may find it helpful.

I was tinkering around with a 1" Green Mountain 1:26 Twist .50 cal today when I decided to run my Bore Scope down and take a little look-see.
WOW!  What I found down there was totally unexpected.

Instead of a small chamber, like that on the T/C, I found something that made me stop and think.....and wonder.
I cleaned the chamber well, took a clean patch on a brass .30 cal brush, and loaded it up with "Dykem Blue".
I smeared that Dykem Blue on, in, and all around the Ante-chamber.
I then took a new clean patch and got it to the very bottom of the Ante-Chamber, then wiggled it around to get the diameter of that chamber....when I pulled it and measured it that puppy was 0..68 deep!

The best diameter measurement I could get with a clean patch was right at 0.450"....
Now here's the thing......

Remember what Rod said about a similar off-shore anti-chamber and reduced loads?

I honestly think I could put at least 40 to 45 gr FFFg in that chamber, in fact I have sometimes thought about doing that very same thing in the past.
This particular Fast Twist shoots a PRB quite well with 65gr FFFg Goex.....My paper-patch load is 110gr FFFg, and I can ring the 150 yd, 18", Saw-Blade "Gonger", with monotonous regularity from the bench.
Off hand I shoot a fairly steady 60% on a good day, less when I'm just not on.
 
I've been thinking about shooting reduced loads with PRB, but what I found today scares me to think there could be a .25 to .50" inch gap between the seated ball and the powder.

Fast Twist barrels are designed to be shot with heavy loads using a conical bullet....and quite likely the base of that projectile will be flat, which means the bullet can not go down below the radius "cone" of the anti-chamber.

And that brings me to this........
I sure as heck don't want to yell Wolf, or start some silly scare.
But, even more importantly, I do want folks to know what's down there in their gun, and the possibility, that when using seriously reduced loads, something possibly could go south on you in a heartbeat....to me it stands to reason. To others maybe not so much.

I would just prefer that everyone is safe, and knows they're safe, when shooting hooked breach muzzleloaders.

Look at the depth of this anti-chamber!
 

Uncle Russ....

[RobD]

is this a green mtn barrel that was made for the t/c?  and if so, that'd be why they had to use an ante-chamber breech plug, since the original t/c barrel has an ante-chamber and you can't fudge on the ignition hole location?  is all of this correct, russ?

the bottom line to an ante-chamber patent breech barrel is the consideration for how much powder it'd take to fill up the ante-chamber.  if it doesn't get filled, 'cause a really light charge was loaded, and there's an air space 'tween the powder charge and where bottom of the projectile ('cause the patched ball or patched bullet can't fit into the ante-chamber), that'd be a prescription for failure ... prolly with dire consequences.

[Uncle Russ]

is this a green mtn barrel that was made for the t/c?

You're right Rob. This is a Green Mountain 1;26 "Drop-in Barrel"...I forget the acronym they were once using for these barrels, I bought it 12-15 years back.

I would have to actually pull the breech plug to see exactly how much powder that ante-chamber will hold, but I have to say it is much bigger, ie deeper and larger than I had ever imagined.....

I had the original instructions that came with that barrel but I can't seem to find them.

Over the years I have had / owned several brand new muzzleloaders from CVA, T/C, and Traditions, and I don't ever recall reading anything about reduced loads in any of the Manuals....
I also shoot a "hunting load" of whatever I am shooting and worked up as best load for that gun, and I have never attempted to shoot a reduced load in anything...with the exception of this one barrel with its fast twist, which everyone insisted I had to do to get it to shoot PRB...and it does okay with 65gr FFFg and a prb, but I had honestly thought of dropping that load much lower.... just to see if it helped anything insofar as accuracy.

When I got that barrel, years ago, everybody was telling me you'll never be able to shoot PRB in that thing!
Well, they were dead wrong!
As far as I'm concerned that was just another old wives tale...that 1:26 twist shoots a PRB just fine.

It is NOT as accurate as my early model T/C in .50 cal, with a PRB, but it will consistently make black at 50 yds off hand.

Now that I've taken a look at the inside of the ante-chamber on that barrel I don't think I will be reducing that load anymore than the 65gr I use now for PRB...that, or just not shoot Round Ball in that barrel at all.

It's really no big deal, others have likely known all this for a very long time.
Still yet, I would recommend everyone be very very careful using "REDUCED" loads in any barrel with a hooked breech and ante-chamber..... I don't know how to make this any clearer, just be careful with reduced loads!

Uncle Russ...

[Hanshi]

That's highly interesting, Russ.  It must just be characteristic of of drop-in barrels they make for T/C and imported guns.  My .40 is a GM swamped barrel (for a flintlock) and has a flat breech.

[ross]

Too many years ago I bought and built one of the first T/C kit Hawkens. The most accurate load I could find for off hand close range targets was fifteen grns. ff . While cleaning I discovered that I was seating the ball on the breach plug and the powder was not filling the antechamber. Well at least it was only 15 grns. For saftey's sake I raised my plinker load to 30grns. Except for patent type breeches I don't know why anyone would incorporate an antechamber that causes a cleaning problem.

[RobD]

... Except for patent type breeches I don't know why anyone would incorporate an antechamber that causes a cleaning problem.

patent breeches and ante-chambers are one in the same, just different names.  the ante-chamber is the "patent breech" and vice-versa.  the prime reason for the ante-chamber is to ensure the detonation takes place well behind the projectile.  clearly, it's not without its own issues.  on the "bright side" however, a dry ball is a bit easier to blow out if the touch hole is removable for dumping in powder. 

[Uncle Russ]

Rob, Don't know if I ever said thank you for pointing this out a year or so back, but I do thank you.

Like many others, I had hear of this thing called a 'Ante-Chamber' before, but I had never really took a look at one until I got a decent bore light.
It was one of those things that not one in one-hundred had actually ever seen, unless they had actually pulled the breech plug.

After actually looking down in one I am certainly glad I was never much on the reduced load theory of saving powder and lessening recoil for targets and plinking.

Anyway, thanks for pointing that out.... waay back when.

Uncle Russ...

[RobD]

from one of my GPR assemblies, after cleaning up all the proofing residue, an ante-chamber breech plug on left with male threads (.336" hole) and barrel on right (.500" bore) on right, with female threads to accept the breech plug.





the sorta amazing thing to me is that, at least using Swiss 3F, i've fired off 17 patched ball shots in a row with a GPR and never did any between shot fouling control.  i didn't load and shoot any more, but prolly could of shot at least a bunch more as well!  you'd think that bp residue crud would get forced down into that narrow ante-chamber and restrict ignition.  nope, didn't.  i might've had some gun flint issues and no spark, or a pan flash because i didn't pick the vent, but heck it just kept on firing. 

this latest one is a .50 and i'm thinking about sending the barrel off to bobby hoyt and have him open it up to a .54 with 1:66 twist, radius groove rifling, and have bobby vise the barrel dead straight.  of course, since it's my finger on the trigger, all that barrel goodness prolly won't mean squat with my kinda shooting and subsequent scores.       

[Uncle Russ]

from one of my GPR assemblies, after cleaning up all the proofing residue, an ante-chamber breech plug on left with male threads (.336" hole) and barrel on right (.500" bore) on right, with female threads to accept the breech plug.





the sorta amazing thing to me is that, at least using Swiss 3F, i've fired off 17 patched ball shots in a row with a GPR and never did any between shot fouling control.  i didn't load and shoot any more, but prolly could of shot at least a bunch more as well!  you'd think that bp residue crud would get forced down into that narrow ante-chamber and restrict ignition.  nope, didn't.  i might've had some gun flint issues and no spark, or a pan flash because i didn't pick the vent, but heck it just kept on firing. 

this latest one is a .50 and i'm thinking about sending the barrel off to bobby hoyt and have him open it up to a .54 with 1:66 twist, radius groove rifling, and have bobby vise the barrel dead straight.  of course, since it's my finger on the trigger, all that barrel goodness prolly won't mean squat with my kinda shooting and subsequent scores.   

 

When I grow up I want to have a lot of money, and be very smart, just like my friend RobD...

That man has a ton of good solid information stored in his head, and another ton of cautionary common sense stored inside all that.
A .54 with a 1:66 twist, with "U" shaped groves. is a good thing when it comes to PRB, and I can say that with a goodly amount of certainty.

I can also say that the "finger on the trigger" skill set, is just as important as the skills of out best barrel makers!

While they continue to practice their barrel making skills, we must continue to practice our "finger on the trigger skills", and never forget, "It's always the Indian, and the never the Arrow by its self". 

FWIW:

Uncle Russ...

[Ohio Joe]

I have to say that Rob's research has opened many an eyes to "what's down there" and even had me looking to see if I was getting that anti chamber clean. Fortunately I am (I just checked). I have to question the reasoning behind even having an anti chamber in a flintlock? (As a side note, I've always felt they were ridiculous in cap lock ignitions - but that's just my opinion).

Thanks for the information Rob. This kind of research is always informative for all.

(As another side note), when zeroing my .50 cal GPR I was (and do use) 2fg Goex powder. I was swabbing between shots and had no issues, but that may be because I was (and normally do all the time) pick and priming (4fg)... Now I've ended up with a good load of 80 grains 2fg, and have tested how many shots I can go without swabbing the bore,,, five... I'm thinking as long as I'm not pushing any fouling down the bore with swabbing - the 2fg powder finds its way home into the anti chamber and the fouling is pushed down on top of the powder with the spit patched .490 ball.

Pretty darn interesting stuff! Thank you Rob!