Re: mark V poor groups
Without seeing the rifle I'll suggest that skim bedding it will probably improve what you're getting, assuming it's not due to technique, scope issues, ammo issues or the barrel heating up. Our 7mm Wby rifles with sporter barrels will do great for the first couple of shots but then at least 2 of them start to walk as the barrel heats up. Both are skim bedded and free floated with good scopes.
FYI the latest B&C we just purchased had quite the "tip up" at the end of the forearm, and there was no way the action would have set in the stock if I hadn't sanded it out with more than just the barrel pads being removed. Be sure your action is fitting somewhat close, but again bedding it will help.