A buddy was telling me about his mark 4 , was on one of the 338, think it was a edge, 200 rnds,failed, made it to 80 next go. I have a mil/mil dropped $1700 on it, only 10 rnds shot but hope it lasts.Side note I have a vari 3 tact, on 9th year on braked 340 WM, NO problem, hoping for same on M4