I had a 243 MKII that would do that, took the gunsmith at Carters Country all of 2 minutes to fix. He was taking a smoke break and seen the rifle fail, (it was brand new) he said give him a minute with it. Took it inside and it has never done it again.

JOC was right. The 270 Winchester on a Model 70 is a great combination as is the 30/06 and 375 H&H