Heavy load data for .62 PRB?

[mark davidson]

Curiosity is killing me. Ya'll know I am in the very early stages of a new .62 cal. rifle project. I am interested in some heavy charge load data for a .62 cal. PRB rifle, probably in percussion but it could end up in flint. I have read by very respected individuals of healthy charges in the 200 grain (2F) range and above. I do not have a black powder loading manual yet. Do any of you have some load data you are willing to share for upper end .62 cal. PRB?  Barrel length will likely be either 36" or 38".  Please share some loads in .62 that you have experience with that are pretty accurate and also pretty hot.  Thanks in advance.

[Bigsmoke]

Mark,
I have been playing with the big bores for about 12 years now.  Here is what I have found.
All of my rifles have had a slow rate of twist, 1:104, except for one with a Rayl barrel that had 1:99, IIFC.  That didn't seem to make much difference.
On my current .62 with a 32" barrel, I target shoot with 135 grains of Ffg.  Out to 50 yards, it pretty much clover leafs.  I am sure someone with better eyes could maintain that further out.  Not me, anymore.
I have run it up to 200 grains to shoot at distant silhouettes.  They go clang, so it must be OK.  I do fall short when shooting at the 400 yard clanger at the rifle range, however.
A while back, I did some chronograph testing with it, and using GOEX Cartridge grade powder, 200 grains gave me 1,994 fps.  Pyrodex Select upped it to about 2004 fps.

[mark davidson]

Bigsmoke,  Thanks for the info. I wonder how much the velocity would change with your charges if the barrel were 36" or 38".  Either way, 2000fps. with a .62 rb is very respectable and ought to pack the punch I am looking for. Have you shot the 200 grain powder charge load off a solid rest (bench) at 100 yards to see just what accuracy it is capable of under ideal conditions?  Also, do you know what the "maximum" 2F safe charge is for .62 cal.?

[woodman]

Mark
 Barrel length changes in velocity are so small as to be almost negligable. About a pound per inch of barrel.
  Back years ago in Muzzleblast magazine they did tests on different barrel lengths on trade guns and that was the results.
 Woodman

[Bigsmoke]

Mark,
My barrel is 1 1/8 tapered to 1".  200 grains is about as much as I want to go or feel I should.
I have shot a few rounds off the bench with those charges, but it is more pleasant with a standing position.  I guess a standing rest could be fashioned, but I just don't care enough to go to the trouble.  
Like I said before, 100 yard shooting takes better eyes than currently reside in my head.  And they sure don't seem to be getting any better as the years go by.

[tg]

I use a .62 smoothrifle usually with 90-100 gr 3f as I only shoot to 50-60 yds it does well at those ranges with a 3" or less group off a rest the bottom paper plate is at 50 yds all shots sharing three patches I scrounged from the garbage under the seat of my truck, I know a guy who has a rifled .62 Hawkinish gun who shoots 150 gr 2f if I recall, and he says it shoots pretty good out to 80 =90yds or so as that is as far as he can get a sight picture, I think my smoothgun would pattern pretty good out there if I could see better but I limit the range to what my eyes
tell me is prudent,the four closest shots below are a 3 1/2" spread offhand, my patches started to fall apart about then or I think I could have kept a few more in tight before my arm wore out (not from recoil) I would think a rifle would snug things up considerably
I would contact the barrel maker for max loads on an individuakl barrel

[mark davidson]

Bigsmoke and TG, Thanks for the info again. I guess when I get a new toy built, I will start at just over 100grains of 2F and work my way up toward 200grains and see where it shoots best and groups best and what the trajectory limits are.  I have no real desire to shoot more powder instead of less just for the sake of more powder; my goal is good "usable" trajectory similar to my .54 with about 100 grains of 2F in it. My eyes are not perfect but are still pretty good. Holding an inch group or so off the solid bench is still very doable for me with a gun that will do it. My .54 will dang sure stroke off the bench and that gives me much confidence in hunting. I hope the .62 I have in mind will do the same thing. I try like everyone else to get close as I can but I want a real firearm like a MLer to at least be able to perform at 100 yards or just beyond as long as my eyes hold up to their end of the bargain.

[Bigsmoke]

TG and Mark,
And anyone else this might pertain to.  If you are having problems with patches burning, what I have found to be a great idea is to load a lubricated cushion wad between the powder and the PRB.  In the case of .62 cal, use a 20 gauge, .54 cal a 28 ga, .69 a 14 gauge, .72 a 12.ga.  That absolutely stops the problem.  Also because it makes a better seal, you get a few fps increase.  And it makes reloading after heavy charges much easier as well.
John

[mark davidson]

bigsmoke, great tip!  I am not having trouble with patches burning through right now but I have not shot more than 120 grains in my .54 and most shooting is done with 90grains cause that is where my sights are right on where I want them. I will for sure keep the idea in mind when I start testing with a bigger ball and more powder.

[Sir Michael]

I use 62 gr. of 3f out to about 75 yds.  and 110gr beyond that.  Seems to work pretty good.  Even these loads burn a lot of powder in a day.

[ridjrunr]

At what gage or cal. would you want to go to 2F vs 3F as far as safety is concerned.I'm just now gettin to know my new to me .69 smoothy.I thought I had read recently that too much can actually be counterproductive.?But that may have been in a rifled barrel only?This is a helpfull and interesting post,Thanx !! ridjrunr

[Sir Michael]

The legal departments of factory muzzleloaders say 2f above .50 cal.

I use 3f in my .62 cal because that is what its maker said to use.  In my 20/# (20 gauge/.62 cal) trade gun I use 2f.

As far as safety is concerned I'm not sure it really makes a difference in factory guns since the quality of the steel used in them far exceed the pressure requirements of either powder.  In hand made barrels I'd go with what ever the maker recommends.

[tg]

I would not be concerned with 3f in the .62 I did use 2f in a .72 I had that had a thin barrel, accuracy would be my only issue as to which powder to use, I usually do not have burning patch problems but went off half cocked thew other day and only had three pieces of .010 ticking to shoot with. One thing I would suggest is to considewr a style of gun with a large wide buttplate (early style)  this type of gun helps distribute the recoil if one gets into heavy loads, I don't know if a slim, curved buttstock type like a Tennesee with a one inch or bigger barrel would be a very comfortable gun to shoot in the larger bores, mine is a swampedGetz 42" 1 1/16 at the breech and 100 grs 3f is not much more than a 20 gauge shotgun with field loads. The main concern with 3f in large bores is the chance of early bore wear due to high pressure spikes and burn thru around the patch and ball,using hot loads  the rule of thumb is to cut the recommended 2f load by 20%, I suspect one would have to go past the point of optimum accuracy or pain tolerance before 3f would be a safety issue in a .62/.69

[Bigsmoke]

The generally accepted practice is Fffg up to .50 cal. and Ffg from .50 through .72 cal and Fg past there.
But like all practices, people deviate from it for whatever reasons.  Some folks find that Fffg shoots best for them regardless of the caliber, and they use the Fffg to prime with as well.
I think the rule of thumb is if you are shooting Ffg and want to try Fffg, decrease the charge by 10%.  Thereby, you theoretically would get the same results but extend your powder supply by 10% or so.
Personally, I prefer to err on the conservative side of things and use either Ffg or GOEX Cartridge powder in my rifles from .45 up to .72 cal.  My preference is the Cartridge Grade, as I feel it is a bit more consistent and burns cleaner.
However, the finer powder will build higher pressures, so, from a safety viewpoint it would be better to go with the coarser powders in the bigger bores.
As with a lot of things, YMMV, and you should test things at the shooting bench rather than take whatever I or anyone else says on subjects like this as gospel.
I have never had the opportunity to run pressure tests on any of my rifles, but I do think it would be interesting to do so.