I purchased a used savage model 114 7mm stw pre accutrigger in pristine condition, gun is beautiful, started off with nosler trophy grade accubond 160gr (red box), and right out of the gate prolly 4th shot blew a primer and noticed the ejector spring had broken and kept the pin stuck out, so put a new spring kit in and start shooting again and had a hard time getting any kind of group, so I changed rings from vortex aluminum rings to steel W.A.R.N.E. rings (scope is a vortex viper 6.5-20x50) and started over, just as it seemed rifle was getting close to zero (+1.6 inches @100yds) I ran out of the older red box noslers and opened a new black box trophy grade accubond 160's (same ammo) first shot was 4 inches higher and couldn't open the bolt, when we did get it open the primer was blown out of the brass, same thing after 3 more shots, even tried another box of same ammo and same thing on the first shot, called Nosler they are swapping out the 160's for 140's thinking it will lower pressure and end the problem. I took the gun to a gunsmith and had head space checked, bolt checked any tolerance that needed checking and gun was fine, he fired 3 different ammo manufactures through the gun and it operated fine, so...Â…Â…...im thinking change brand, started shooting HSM 168gr berger VLD and the first shot right out of the gate was dead center +1.6 @ 100yds (hard to believe) then on the second shot it was 7 inches lower and 2 inches right, third shot was nearly bullseye 1 inch left, fourth shot was 2 inches high and 2 inches right (haven't turned a dial yet) I'm scratching my head at this point, just looking at the riflings they look fine as far as wear goes so now im thinking maybe this gun has been fired quite a bit before I got it and maybe copper fouled, I spent 3 hours tonight using bore cleaner and copper remover cleaning this thing and constantly got a black then green residue on patches for ever before I finally started getting clean patches, assuming the green was tarnished copper residue im starting over with the HSM ammo tomorrow if this doesn't tighten the group on this rifle what else can it be???? I know bedding the stock may help some but this rifle should at least shoot 1 1/2 no more than 2 inch groups at worst at 100yds...Â…Â…Â….. Your thoughts????