I was given my neighbors ranger Ruger M77 to tinker with because he was getting 12” groups with it. Multiple brands of factory ammo. Gunsmith said his rifling was fouled or the barrel was shot out. We cleaned the barrel and I shot half a box of shells and I could get 2 shots to group and the next 2 would be 6-12 inches away in random directions. I loaded up hand loads of 117gr hornady interlocks and IMR4831 and same results. 2 shots within 1.5inches and the next would be a flyer.
At this point I am think the scope is the culprit so I swapped it and got the same results with factory and hand loads.
Do you think the barrel is shot out? He doesn’t know the History of the rifle but he has had it for years and has only deer hunted with it so maybe a box of shells a year.
Thoughts?
