GMX .30-cal. 150-gr. bullets have a crimping cannelure .294” in dimeter and a pressure relief groove below that .293” in diameter. The narrower than bore diameter grooves provide a place to ...

I measured the crimping cannelure on a 180-grain, .30-cal. CX bullet at 0.294" in diameter and the pressure relief groove below at 0.293" in diameter. A fired and recovered 165-grain, .30-cal.

(All .22 rimfire bullets are still heeled and outside lubricated except for the .22 Winchester Magnum Rimfire.) Smith & Wesson’s 1860 patent shows three lubrication grooves or cannelure along ...