Try this - with the barrel off, thread the can on and

by Slow Hand , Indiana, Saturday, July 20, 2013, 23:45 (4088 days ago) @ John K.

Yep, I always look down the bore, even for a trusted machinist. You're shooting a 7mm bullet through a .30 cal can, right? That should give you even more 'wiggle' room. Speaking of wiggles, you might try shooting a couple shots at a new target up close, like 10-15 feet without the can. You may have some stabilization issues with that short barrel. I know little about the 7-08 but if a lighter bullet is available, try that and see what happens. I know that some various subsonic loads don't stabilize at the muzzle, but settle down pretty quick, and you can get baffle strikes. If you see an oblong hole at very close ranges and round holes further out, that could be your issue.