Bought a new semi-automatic in 7.62 NATO (I do not want to call out the Company just yet to be fair), and shot some cheap 1978 SB 7.62x51 NATO ammunition to site the rifle in. The groups were horrible (4-6in at 100 yards). I pulled a bullet from one of the unfired rounds, and used that to index my shoulder length. I would like feedback as to normal case shoulder movment that you a seeing in NATO headspaced barrels.
The once fired rounds neck's were moved forward 0.0165in averaged for 11 cases (n-11). I had one fired case with a split neck. I switched to American Eagle 168g SMK, and same shoulder movment was noted. The shoulder movement was not consitent between each measure case, but the variation ran between 0.0125-0.0300in.
I called the manufacture of the rifle and was told to shoot 200-300 more rounds to let the rifle settle in, and that the headspacing was checked twice on each rifle. he said that the headspacing was set tight on the NATO and should be loose for the .308.
I tried some 308 loads this AM, and still shoot a 4in, 5round group (Yes I changed scopes, checked base screws, mount screws, and ring screws).
The once fired rounds neck's were moved forward 0.0165in averaged for 11 cases (n-11). I had one fired case with a split neck. I switched to American Eagle 168g SMK, and same shoulder movment was noted. The shoulder movement was not consitent between each measure case, but the variation ran between 0.0125-0.0300in.
I called the manufacture of the rifle and was told to shoot 200-300 more rounds to let the rifle settle in, and that the headspacing was checked twice on each rifle. he said that the headspacing was set tight on the NATO and should be loose for the .308.
I tried some 308 loads this AM, and still shoot a 4in, 5round group (Yes I changed scopes, checked base screws, mount screws, and ring screws).
