01-24-2016, 05:02 AM
I use the tool to check square on all uppers. Most have been square lately, so no lapping needed, but in the past, I've found many that were way off.
The big problem is bolt lug engagement. If the receiver is out of square, you can have major problems with only 2 bolt lugs taking the load of bolt thrust and shear forces.
Aside from that, it contributes to accuracy like blueprinting a bolt gun action.
The big problem is bolt lug engagement. If the receiver is out of square, you can have major problems with only 2 bolt lugs taking the load of bolt thrust and shear forces.
Aside from that, it contributes to accuracy like blueprinting a bolt gun action.
NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com