Gun: Glock 42 Load: Mixed headstamps, mostly one fired. COAL is .950", same as Freedom Munitions ammo that uses the same bullet. Winchester small pistol primers. Powder is 3.4 gr of WW231. Bullets are X-treme 100 gr plated flat point, .3551 diameter. Crimp is just enough to remove the flare, both my micrometer and my magnifying glass say the loaded case mouth is neither belled out nor crimped in, though it does leave a moderate ring on pulled bullets but definitely not through the plating. 10 rds average 845 fps with an ES of 45 fps from my G42. Loading Eqpt: Dillon 650, Dillon dies. Expander die mics .3530 I've fired over a thousand of these loads through several G42's and they work well. Recoil and accuracy is about equal to various factory loads I've tried, not a sniper rifle but can stay on a silhouette out to 50 yds. When I first got the .380 conversion from Dillon, I loaded up a few rds with different headstamps and hand-cycled them through the gun, then measured bullet setback which was minimal- maybe one or two thou for each trip up the feed ramp into the chamber. But after loading a bunch more, for some reason I re-did the setback test. This time the results were not so good. Each time hand-cycled set the bullet back by an average of .005, so three loadings would set back about .015". I'm not sure what to make of that. Obviously, the ammo works well in normal firing. Since this is range practice ammo, I don't usually re-chamber any one cartridge more than once. By coincidence, it might get re-chambered twice. Bullet setback can raise pressures drastically in 9mm, but the tests I can recall seemed to start with .020" setback and go more (well, less) from there. And the .380 is a relatively low pressure round. So perhaps I don't really have a problem here. Just remembering to avoid re-chambering any individual round more than once might be enough to keep things safe. OTOH, I'm not sure what to do differently even if I'm determined to eliminate the "problem". Crimping is not the way to prevent setback, and anyway with plated pullets that have no channelure it would probably make things worse instead of better. The expander plug could be polished down a couple of thou, but that might cause the plated bullets to get "swaged" down by the cartridge case and destroy accuracy. And it might not solve the problem, since the length of the bullet that is actually gripped by the case mouth is so short. Comments and suggestions? Thanks.