Triple-7: That Old Black Magic… Sort of.

Recently I became re-acquainted with black powder ( .) I had a very limited supply and quickly ran out, so I asked after some more at Pinto’s. Nope; they only had black powder substitutes, Pyrodex and Triple-7. It seems that as black powder is classified as an explosive there are some hassles involved in keeping it on-hand and selling it- hurdles that local gun shops have elected not to deal with. (Because of its classification as an explosive Washington State residents are only allowed to possess five pounds of it.) The nearest place that does sell it would require a two-hour round trip.

I looked into ordering it online, but hazardous material shipping rendered the price unattractive. I used Pyrodex a lot when I was shooting cap-and-ball revolvers in the early 80’s, and I was not impressed with either its performance or cleaning, After some research I decided to try my hand with Triple-7.

This powder consistently produces higher velocities than Black Powder volume-for-volume. I’ve seen some people worried that it generates higher pressures than BP, even insisting that it has to in order to get higher velocity. Someone needs to do some studying…

BP is a low explosive; maximum pressure occurs in the chamber and drops off rapidly as the bullet travels down the barrel. Triple-7 is a very fast burning powder; maximum pressure still occurs in the chamber, but it falls off much more slowly than BP as the bullet travels down the barrel. In other words it has a longer pressure-curve. It doesn’t push harder, it pushes hard longer. In a typical muzzle loader this creates an average of 17% more velocity than BP without an increase in peak pressure.

Naturally in shorter-barrelled weapons this effect is less pronounced. The manufacturer recommends loading metallic cartridges almost exactly as you would BP, but with less compression. Typically one compresses BP in a cartridge about 0.10″. Triple-7 recommends loading with very little compression but no air-space under the bullet.

Following this recommendation I loaded .44 Colt, .450 Adams and .44-55 Walker with FFFg Triple-7 and tried them at the range. Without a chronograph you can only tell so much, but recoil can be informative.
Starting with .44-55 Walker I loaded 200 gr..451- heel-base SWCs over a charge of 55 gr. of Triple-7 (measured by volume.) Extrapolating from published data and considering Thumper’s 3-1/2″ barrel the math suggests that, all things being equal (and they never are,) I should be getting 1200+ fps for approx. 640 ft./lbs. of energy at the muzzle. Recoil of the 3-1/2 lb. gun is similar to an L-frame .357 Magnum, so I find this believable. I really need a chronograph…

I found this load to be quite accurate at close range; longer range testing will have to wait, owing to my limited supply of brass… which I am working to fix!

‘Thumper’ with its 44-55 Walker ammunition

For .450 Adams I loaded 200gr. LRN-FP bullets over a charge of 8.0gr. of Triple-7 (13gr. by volume.) No idea of the velocity, but wow! My best previous load was the same bullet over 4.0gr. of Trail Boss, which recoiled like a .38 target wadcutter. The new load had significantly more muzzle-blast and recoil. After firing it in a .45 Colt and one of my modern conversions I tried it in the Webley RIC. Quite a difference from the Trail Boss load. It was like shooting .38 Spc.+P in an air-weight J-frame; at least bordering on unpleasant. I can finally understand why some people complained of the recoil of these guns. I won’t be putting a lot of these rounds through my antiques.

My Model 1883 Royal Irish Constabulary. A bit of a handful with the Triple-7 loads…

I loaded the .44 Colt with the same bullets as the .44-55 over 28gr (by volume) of Triple-7 showed significantly more recoil that the same round loaded with 6.5gr. of Trail Boss, but not notably unpleasant in the guns I was shooting it out of.

My Custom 1858 ‘Brasser.’ The .44 Colt loads performed quite well in this gun.

It was a very informative range session. Clean-up was similarly informative. The guns were dirtier than if I had been using smokeless powder but not nearly as dirty as BP or Pyrodex. I cleaned the guns by cleaning them. I used Hoppe’s #9 on the bores and Break Free CLP for the rest. Not much more effort than normal, just that the cleaning patches were dirtier and I used more of them.

Brass was a bit of a different story; the Triple-7 left it far dirtier than smokeless powders. As an experiment I put the brass from my test session in a gallon zip-lock bag with hot water and a few tablespoons of Barkeeper’s Friend cleanser. I shook the back vigorously for a minute or two, then let the brass soak for about a 1/2 hour, then dumped it into a colander and rinsed thoroughly with hot water and put it in a 200 degree oven to dry. This produced acceptably clean brass. Not pretty, mind you, but at least not all gooped up. Next time I’ll follow the suggestion of a buddy and try boiling the brass and see how that works out.

I’m pretty pleased with how the Triple-7 has worked out so far. I’ll continue to report on how it goes with this propellant. Finally getting .44-55 suitably dialed-in has led to some interesting thoughts- like ‘wouldn’t it be great to have a single-shot carbine chambered for this round?’ I’ll be playing around with that idea…

Michael Tinker Pearce, 20 May 2019

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