My shooting friend is working with a 1/8 AI 243. Working with virgin brass (not formed yet) he was loading 48 grns-H4831 below the 6mm 87 VMAX. He worked up to this load with no obvious pressure signs. After setting out toward the lands closer, he loaded quite a few of the same. The following day, the bullets were blowing up down range. For you who might not have seen that, it looks like a little puff of smoke 25 yards out or so.

We hadn't crony'd yet, and when we saw the smoked bullets, he wrote Hornady tech email. They said that 3300 fps developed 300,000 rpm and would take the Vmax apart. I concur with the rpm, can't crony cause I think I might smoke the chrony with an exploding Vmax.

Has anyone else seen this at this speed? I'm shooting from 1/8 standard varmint 243 barrel @ 3100 with no problems. 1/8 is twist.