357 Mag ??

[BABore]

I recently snagged a Lyman #358156 2-cavity mold on Ebay. It was advertized as brand new, but was far from it. Since I only paid $18.50 I wasn't overly PO'ed, especially since it drops 0.3605" boolits. A $5 rebuild kit corrected all of its problems.

I casted up a bunch of WW+1% tin bullets, GC and sized them at 0.358" and lubed them with Alox and Motor Mica. I tried them out with my standard plinker load of 5.0 grs of WW 231 and CCI 500 primer. This load with the Hornady 158 gr swaged SWC usually gives 1 1/4" 50 yard accuracy in my S&W 686 8 3/8 at 1,000 fps. So far, the 358156 bullets are grouping around 2 1/4 to 2 1/2". I also tried some with homemade Saeco green lube and they were even worse. I'm wondering if I'm driving them hard enough. The soft (5 Bhn) swaged bullets do great with leading only after several 100 rounds. The 156's are running at 10 Bhn plus they're gas checked. No leading at all with these. Any thoughts on this? I know this is somewhat premature since I've only tried one powder, and one weight but this load has been pretty successful in several guns with different lead bullets.

I slugged the bore, but can't measure the diameter well due to it being a 5 groove. I know it's just a tad tighter than the cylinder throats which measure 0.3572".

[9.3X62AL]

If the throats are dimensioned as you indicate, sizing isn't the first thing I'd modify. I would try some velocity/pressure variations before doing dimensional gymnastics. I've run #358156 to 1500 FPS in my Bisley Blackhawk with very fine accuracy.

You also have the option of two crimp grooves with this design. If your revolver's cylinder length allows it, seat the bullet out to the lower crimp groove's depth, esp. with the heavier loads. That has been known to modify results in some cases.

[Buckshot]

.............to get you within less then a thou of your actual groove dia. Get'cher dial guestimaters out, wipe the blade faces and check zero. Using the knife edge at the end of the jaws, measure your barrel width as close to the bitter end of the barrel as possible. Probably have to measure at 9 and 3 if it has a full lug and ramp.

Okay, write that figure down after sample measuring a few times. Hopefully you have at least one groove co-incident at 9 or 3 (if that's where you had to measure). With one jaw knife edge in a groove and the other on the outside of the barrel, again at the bitter end, record this number.

Now double your last measurement and subtract that from the first barrel overall width figure. This should have you on, or within a half thou of the actual groove dimension.

............Buckshot

[StarMetal]

BABore,

For the poor folks that don't have a pipe mic or v-mic do this. Taka piece of metal 1/8 inch thick, 1 inch long, and 1/4 inch wide. Bend it dead center at a 90 deg angle. Now file off some of the outside bottom of the V so it has a flat. Now you take something round like a 3/8ths drill bit shank and mic it. Then mic it with the V in place and the shank inside the V. One mic anvil should touch the drill bit shank, the anvil should touch the flat your ground on that V. Then you subtract the two and the number you get is your base number to subtract when micing 5 groove bullets. Here's a pic of the V. I do this and it works alot closer then Buckshot method.

Joe

[BABore]

I ended up getting it done accurately with a v-block and height gauge with dial indicator. The bore measures 0.3565". The cylinder throats measure 0.3572". My sized bullets measure 0.3581". IMO everything looks good. The gun is a fine accurate shooter with any jacketed and the Hornady swaged lead SWC. Since the WW bullets are running 9-10 Bhn, and have GC's, I'm thinking I might need to kick them in the butt a little more. I know I can drive them fast, 1,250 to 1,400 fps. What I'm going for is a plinker load, 900 to 1,100 fps. I figured I'd start by bumping up the WW 231 a bit first. I'm also going to try some 2400 in the 10 to 13 gr range. Lyman has something like 14.7 grs of 2400 for their best accuracy load, but it going to be doing 1,350+ out of my 8 3/8 bbl.