Haven't did any testing for the 357 in awhile (years). Always used 4" or longer bbl's so it really didn't matter. Any 158gr or heavier bullet using powders like unique or slower would result in a pretty good thumper.

Picked up a l-comp 587 7-shot that is supposed to have a 3" bbl. The bbl shroud is 3" long which is a good thing (full length ejector rod for the long cases). The actual bbl is only 2 1/2" long with a 1/2" comp in the end of the bbl shroud.


I tested several different bullets just to see how they would perform. Was really interested in the Mihec 359640 bullet so that's where I did the most testing.


I used 2400, mp-300 & h110 for powders. And used the 2 1/2" bbl'd l-comp 586, 4" bbl, 6" bbl", 8"bbl Dan wesson with the cylinder gap set @3/1000th's. And a 10" contender bbl. I've had several 4" & 6" dw bbl's over the years. I kept the ones that performed extremely well (higher than usual velocities) & got rid of the rest. I don't use/shoot the 8" bbl that much & really need to find a good replacement for it.


I set the chronograph up 10' away and leveled it. Then measured the height of the muzzle and put a target up down range with the bullseye the same height as the muzzle/rest & did 20-shot test strings.

158gr hp 2400 14.7gr test load:
3" bbl ='s 1197fps
4" bbl ='s 1257fps
6" bbl ='s 1343fps
8" bbl ='s 1406fps
10" bbl ='s 1610fps

158gr hp mp-300 18.5gr test load
3" bbl ='s 1124
4" bbl ='s 1261fps
6" bbl ='s 1404fps
8" bbl ='s 1477fps
10"bbl ='s 1672fps

158gr hp h110 16.0gr test load
The 16gr h110 load pretty much mirrored the 18.5gr mp-300 load. All bbl lengths were within +/-10fps of each other.

The faster burning 2400 did better in the shot 2 1/2" bbl.
All powders were pretty much = in the 4" bbl.
The slower burning mp-300 & H110 really shined in the 6" and longer bbl's.

I'm going to stick with the 2400 powder and work on accuracy. I can go up to 15.5gr of 2400 so there's a lot of wiggle room/testing that can be done between the 14.7gr & 15.5gr load.

The mp-300 & H110 are going to be saved and used for hot loads with my home swaged jacketed bullets. Home swaged jacketed bullets for the 357mag


Home swaged jacketed bullets for the 44mag.


It's hard to beat 2400, I use it in the 357 & 44mag, 38spl p+ loads, hot p+ 44spl loads and 1600fps to 2000fps rifle loads. It's not hard to find the sweet spot with cast bullets in rifles when using 2400. The groups shrink up like the 18.7gr 2400 load (upper left). 10-shot group @ 100yds from a 308w that measure 1 3/8" outside to outside of the holes.