13.5 of 2400 in .38 cases with a 358156 gets me 1300 fps out of a 4 inch model 66. Great load but the accuracy isn't there for me in the 627. Tough pill to swallow less powder getting more fps out of a shorter barrel.
I load 14.5 gr/2400 in .357 cases, get about 1250 fps in a couple 6” guns, a 686-2 and a 27-2. Those are with 158 grain jacketed bullets, accurate and easy extraction.
Got up to 17.0 H110 yesterday with the 158 xtp. 5 inch 627. Velocity averaged 1209 fps (seems low) ES and SD were dick nothing. Went to 17.5 and velocities jumped up to nearly 1300, but ES and SD was all over the place. Cases fell out of the cylinder, no flat primers.
Might give AA # 9 a try.
Checking my notes, using a 4" S&W M-19 .357 with a 158 gr. XTP: using 16.7 gr. of H-110 & a CCI magnum primer, I get 1217 fps. Using 14.8 gr. of 2400 & a Winchester regular primer, I get 1208 fps. These are the two "go to" loads for me with these type bullets. You should get a bit better velocity with the longer barrel.
Two things happened in my world recently- I've taken a renewed interest in my .357 Magnum's, and I noticed that I have STUPID amounts of fast burning powder such as Clays, 700-X and Bullseye/IMR-Target. I carry a SA .357 a lot around the place doing chores, feeding the cows, etc., but rather than carry full-house, ear-splitting loads I typically carry a 158-173 gr. cast SWC running 1000 fps or so. So a few days ago I set about testing loads with IMR-Target, which is for all practical purposes Bullseye. 6.0 gr. of Target and a cast 158 gr. SWC netted 1140 fps from a 4 3/4" barrel, and that's still a full grain below max. Velocity from my 20" Rossi was well north of 1300 fps. I'm guessing were I to go to 7.0 grs. velocity in the revolver would probably be 1250-1300 fps. With the 173 gr. cast (358429) SWC, velocity was right at 1100 fps from the revolver and 1300 from the carbine.
I've never really seen the use in very slow powders in revolvers. I've loaded 2400 and H110 in my .357's, but found that I can get close to the same velocities with 50% lighter charges of Blue Dot.
I guess my point is- Why use all that slow burning powder for few if any gain in velocity when faster burning powders will do the same with lighter charges?
