Best powder for med. to hot loads, .357 revolver and carbine?

[Vern Humphrey]

Unique works well up to moderate loads, 2400 for moderate to heavy.

H110/296, Lil Gun or 300MP for peak velocity, regardless of barrel length.

I use Li'l Gun for .357, .45 Colt and .22 Hornet -- and in my opinion it can't be beat in any of those cartridges.

 

[WrongHanded]

Sounds like you should test load some of the 4227 load with magnum primers for a longer burn. I haven't used it in 357 but like it a lot in 41 and 44 Magnum and heavy 45 Colt, using whichever primer the data calls for. Lately I have been using Winchester WLP, which doubles as magnum, so it doesn't seem to be critical.

None of the data I have calls for magnum primers, but I don't see any harm in trying it out. I did notice that 15gr of 4227 pretty much fills the .357 case (accounting for bullet space of course), so perhaps that's why it's burning more completely than lower charges.

 

[Jesse Heywood]

None of the data I have calls for magnum primers, but I don't see any harm in trying it out. I did notice that 15gr of 4227 pretty much fills the .357 case (accounting for bullet space of course), so perhaps that's why it's burning more completely than lower charges.

My best results with 4227 include a compressed load with magnum primers.

 

[CraigC]

I use Li'l Gun for .357, .45 Colt and .22 Hornet -- and in my opinion it can't be beat in any of those cartridges.

Warnings about erosion scared me away from Lil Gun and 300MP might have it beat anyway.

 

[Toprudder]

Warnings about erosion scared me away from Lil Gun and 300MP might have it beat anyway.

I have a pound of Lil Gun that I intend to try in 450 Bushmaster, but the warnings (whether founded are not) have me not wanting to try it in my revolvers.

As for 300MP, I was not that impressed with it in my 5" GP100. I worked up loads to test and reached a velocity plateau long before I reached the max published charge. I did not get any more velocity than I did with 2400, and the 2400 was more accurate. It did not make sense to me at the time, as the published load data showed 300MP performing much faster than anything else. I put the 300MP at the back of the storage bin for the time being. Then I picked up a 16" Rossi 92 and I remembered the 300MP. When I went back to look at the published load data for 300MP, I noticed the length of the barrels used and they were 8" (Hornady) and 10" (Alliant). I worked up the same load range as before, and this time I saw a pretty linear velocity increase with an increase in charge. I got a full 200fps faster velocity from the 300MP than I did with 2400, using 158gn XTP/FP bullets. That was at the accuracy node, 0.6gn under max published.

So, if you have a long barrel revolver, it might be worth trying, otherwise you might not get the results that the published load data would suggest. I would like to hear your results if you try it.