I'd like to ask all the experts out there about an accuracy issue a buddy is having with his Marlin .30-30. When he first bought it (used), it would print 5-6" groups at 100 yds. We both tried with the same results. I suggested it might be the scope/mount, so we looked at the mounts and sure enough one was loose. So we tightened it down and expected the groups to tighten considerably. While they did get better, they were still only around 3-4 inches. I know lever actions aren't benchrest guns (after all, Guide Guns are a joke) but I expected better than 4" groups from a Marlin. So I'm a bit perplexed. Here is the exact sequence noted with multiple groups and different brands of ammo. First and second shot are within an inch of each other, then 3rd shot is about 4 inches away, then 4th shot is back by the first two shots. So without the one flyer it would be 1-1.5" groups. But the flyer is always present. My only other theory having closely examined the rifle is that the original owner was overzealous about cleaning from the muzzle end as the crown appears to be damaged. I can't see any major nicks to the rifling with the naked eye but it does appear something bad happened. Could that cause the flyers? We've shot with Remington, Winchester, and Leverevolution ammo. The scope is a Simmons 3-9X with see-thru mount. My buddy is considering just selling it, but I'd like to get some opinions. Thanks.
P.S. We're both good shots, so don't blame us