99merckx
06-20-11, 13:35
In the last couple of weeks we've been messing with flashhider tension on several precision builds that have been floating around here.
Besides making sure we've used good barrels, (always a good place to start), and making sure that the crown and threads were concetric with the bores (we do that), we were still having some trouble with a MK12 SPR build, and a 6.5 Grendel SPR. Just could'nt get them to group they way we wanted, (we were getting 1.5-2" 5 shot groups @ 100yrds., unacceptable). Then I read someware that the AMU guys only put enough tension on their muzzle devices to clock them up, and then loc-tite them in place. There is some lapping of the crush washer to get this to work, of course. So I cranked off the adaptors on both and did that.
I shot both rifles this past weekend and both shot just under 1moa.
There is still some stuff to do to these guns, but at least in these two cases, this method seemed to help. POA shift was someware around
7"x3" afterwards. This is a clue, I think.
Besides making sure we've used good barrels, (always a good place to start), and making sure that the crown and threads were concetric with the bores (we do that), we were still having some trouble with a MK12 SPR build, and a 6.5 Grendel SPR. Just could'nt get them to group they way we wanted, (we were getting 1.5-2" 5 shot groups @ 100yrds., unacceptable). Then I read someware that the AMU guys only put enough tension on their muzzle devices to clock them up, and then loc-tite them in place. There is some lapping of the crush washer to get this to work, of course. So I cranked off the adaptors on both and did that.
I shot both rifles this past weekend and both shot just under 1moa.
There is still some stuff to do to these guns, but at least in these two cases, this method seemed to help. POA shift was someware around
7"x3" afterwards. This is a clue, I think.