I recently went through a very trying experience with a .357 magnum in a 10" Contender. I had several molds -all plain-base- that have proved satisfactory in the past - albeit for paper punching, with revolvers. With the T/C, I could not get decent groups at 25yds. I tried 4-5 different bullets, different alloys, several different lubes, and 3-4 different powders, as well as varying the seating depth, without success. Groups would be around 3" wide by 8-10" high, regardless of the load/bullet.
My goal was an acceptable group (2-3"@50yds?) with at least a 150gr bullet moving at 1500-1600fps. This was to be a hunting load for deer and feral hogs. I admit, I did not try with the lighter "target" loadings, nor with wadcutter bullets. They simply didn't fit with my goal.
I finally purchased a Lyman 358156 AR gas check mold. Viola! Instant success. A previously-tried load of 15.5gr H-110 with this bullet (163gr. checked & lubed) will put five into 2" at 100yds.
At no time, throughout the testing, did I experience any problems with leading, nor did recovered bullets show signs of skidding. All bullets tried were closely inspected, and meticulously culled. All plain bullets were of the flat-base type, no bevel-base. The gas check seems to have cured the problem, but I have no Idea why. Can you shed some light on this?
