powerful black powder loads for 357?

I think you could probably get 30 grains or so with compression.

With some FFFG it wouldn't be anything to sneeze at, and yes, I think you COULD hunt medium game with it in an EMERGENCY.

Oh probably something like 1000-1200 FPS from the 5" barrel and a couple hundred more from a 20 inch barrel.

Which black powder? Regular GOEx or Olde Eynsford or Swiss?

Here is a review of someone using a 250 grain, 45 Long Colt generating 750 fps and 312 ft lbs. of energy,

"I bought these to try in my new Colt Single Action Army and are completely happy with them. Very accurate and cleaning is easy after using them. I'd recommend them to anyone. I even used them to shoot a white tail deer and it dropped it in its tracks at 35 yards."

Those numbers are easily duplicated and surpassed in a 45 Long Colt or 45 Schofield case but I don't know how much black powder you can stuff into a 357 case that will get you up to those numbers to be able to hunt medium sized game. I doubt it.

I found your question intriguing, so I tried it.

I filled a .357 Mag case with FFg powder to the brim; it took a hair over 29 grains of powder.
Then I seated a 158 grain bullet on top of it (home cast Lee RNFP). It took some force on my Dillon 550 press but I was able to seat this bullet to the crimp groove. I then removed the bullet with an inertial puller, topped off the case with more powder, and tried to seat the bullet again. No go.

So with my equipment, I think 29-30 grains of FFG is about all I can get into a .357 Mag case. I do not have a chronograph so I have no idea what velocity this would produce. I'm sure I would not want to be shot with it.

The chambers on my Uberti 1851 Navy percussion revolver hold 30 grains of FFG, but I'm not sure I could completely seat a ball far enough into the chamber with the cylinder on the gun. The round lead ball weighs about half the 158 grain bullet so it will not be as energetic. I'm sure the ballisticians here can provide estimates. But a .357 Mag with a case full of black powder is going to be in the same ball park as an 1851 Colt ...it certainly is not going to approach the performance of a .357 Mag using smokeless powders.

I only have FFG on hand, but you would get a few more grains into the case by using FFFG, and consequently a few more FPS. I am not convinced it would be significant.

I don't know what brand of case you are using, but I can only get 25 grains of FFG into my Starline .38 Special cases...I just measured it. My .357 Mag cases hold more than my .38 Specials; I don't understand the basis for your comment about a .38 special having more capacity than the .357.

In any case, I don't think the few grains one way or another are going to produce dramatic differences in performance.

If you seat the bullet out to .357 OAL in a 38SPL case you will get a few thousandths more room from the thinner case walls but I doubt you could tell. I shoot 357 with BP in the revolver and use 777 in the rifle. Both loads get the 158gr RN or RNFP. By weight it is 22grs FFFg or 15grs by weight of FFF size 777. You might get more in if you can seat the bullet out to a longer OAL but my 92s are finicky about OAL so I use what reliably fees as my OAL which varies by bullet shape. The 777 loads have significantly more recoil and velocity than the BP but less BOOM. If you want more smoke, power, and accuracy I'd recommend 777 especially if you are entertaining the thought of hunting with it. If you forcefully cram the bullet down hard and overly compress the powder your accuracy will go to hell with either BP or 777.

PyroP will compress a lot. You might be able to fill the case to the mouth and seat a 158gr bullet on top and get a shootable OAL. PyroP will give more umph than BP because you can pack down a greater volume of it.

Out of a revolver with a 158 grain bullet your muzzle velocities are probably going to be in the 800 to 900 FPS ballpark for either the .38 or .357. I have real doubts that you could get 1000 FPS with either cartridge based on load data I see in the cowboy action loading tables, but I admit I am guessing. The most accurate loads in these tables are about 20 grains for the .38 Special and about 23 grains for the .357 Mag. ("Action Shooting Cowboy Style" by John Taffin; Krause Publications, 1999) You could probably get 1000 FPS out of a rifle, but your original post specified a revolver.

justin22885 said:

pyrodex and 777 are completely irrelevant for my question.. if i can go to the gun shop and buy a jar of powder im just going to buy power pistol... the question is about how much you can actually squeeze out of 357 if youre forced to use (quite possibly homemade) black powder in the absence of smokeless

Click to expand...

Enough to kill something but way short of a normal 357 Mag. Otherwise the 357 would have never been developed.

The only way I know for sure to answer your question is for you to chromo the loads you want to use and make your decision based on those facts.

I hope you will report the results of your range tests.

Yes, as I suspected, 30 grains of powder.

But I'm sure my initial velocities were too much, no doubt. It would deliver performance much on par with a standard Colt Navy loaded with conicals, probably a little more.

I can't see any advantage to this at all except making a bunch of smoke and trashing your modern revolver or rifle. The numbers just ain't there for this experiment with a 38 caliber.

Remember, at one time, the .32-20 was considered an acceptable deer caliber.
If you are hungry enough a ".36-30" would do the job.

What revolver are you loading for? A Ruger will easily digest loads that would be abusive to a Colt repro.