Maybe I missed it... But someone posted about using squib charges here and it was left alone by the mods?! I've never considered squibs or duplex loads to be advisable, safe, nor normal. If you think that you need them, you probably are cutting a safety or common sense corner somewhere and trying to make up for it with another bad idea..
My.. 02 USD
My post #91 addressed the potential for
safely using a 10 grain squibb charge of fffg black powder under any of the available black powder substitute propellants in a
sidelock, flintlock, muzzleloading rifle.
Except for in a roundabout way referencing the possible total number of 10 grain squibb charges one might realize out of a pound of fffg black powder; I really
was not speaking towards percussion rifles at all. Either sidelock, or inline.
With its essentially open breech design, as a result of the need for a touch hole drilled into the side of the barrel to effect ignition of the main powder charge in the barrel from the priming charge in the pan of the lock; the likelihood of an over pressure situation occurring in the breech of a modern flintlock as a result of combining a 10 grain, fffg granulation, squibb black powder charge with
any of the substitute powders,
to include BH209, is virtually nonexistent.
Is it theoretically possible to blow up a modern steel, properly breeched, flintlock barrel rifled for patched balls? Using a 10gr squibb charge of fffg black powder under any
reasonable charge of BH209?
Yes, it absolutely is possible. Is it likely? In my opinion, not very. It would require some very serious stupidity on the shooter's part for such an over pressure situation to cause a flintlock barrel to burst. Or, for the breech plug to fail.
Could a flintlock, fast twist barrel with shallow grooves, such as the .50 caliber Pedersoli Hawken Hunter (1" octagon × 28.375" long × 1:24" twist), be overloaded with a 10 grain fffg black powder squibb charge, a 120 grain by volume BH209 main powder charge, a .54 caliber wool wad, and a 600 grain No Excuses lead conical? Sure it could. Would the above theoretical load result in a dangerous over pressure situation? In my personal opinion having shot flintlock flintlock rifles for the better part of 30 years, I don't think so.
Recoil would be off the charts uncomfortable. The jet of flame escaping to the right of the shooter would be fearsome, both in length (approximately 48"-60" long), and intensity. Anyone caught in the flame jet from such a load coming out of a flintlock rifle's barrel, would suffer at least a 2nd degree, if not 3rd degree burn. To escape with only a 1st degree burn would take some serious luck.
The only way a squibb black powder charge, in conjunction with a black powder substitute main charge, could result in a dangerous over pressure situation, in my opinion, is to double/triple load the barrel with multiple squibb charges, multiple main charges, and multiple projectiles.
Or, to not fully seat a projectile onto the squibb/main charges, resulting in an air gap between the charges and the projectile.
The
vast majority, probably 99%, of all flintlocks are rifled to shoot a patched ball.
Most patched ball barrels shoot most accurately with powder charges under 100 grains. Most big game animals are killed at distances under 75 yards.
Anyone desiring to shoot any of the substitute powders in a flintlock rifle due to a shortage of real black powder, and thus requiring the use of a squibb charge of black powder under the substitute powder, should certainly exercise appropriate caution in their load development. The use of a chronograph while developing such a load, would be a wise move.
If the current situation with Goex results is a black powder shortage, and I am faced with not shooting my flintlocks at all, or intelligently developing duplex loads using a squibb charge of black powder under the main charge of the substitute powder, then that's exactly what I intend to do.
I feel comfortable knowing that someone like Herb at the American Longrifles Forum has already paved the way with some extensive research, and chronograph work, using his handmade. Leman, .58 caliber, flintlock short rifle with its 24" long barrel.
