just a thought but i think it would be VERY much not a good idea to shoot the mach 2 in an HMR chamber. think about the neck expanding, slamming into your chamber and when you eject them they would come out looking like a mini .357 mag.
not to mention the metal fatigue of your chamber after all that. and the leading/copper fouling from the bullet not being aligned perfectly with the bore.
and also burnt powder gunk keeping the HMR from chambering all the way- leading to excess pressures.
not me, man.
