6.5 Grendel PTG Reamer

[Drifter]

This explains one of the stoner barrels I have perfectly. It is .035" short in the throat! With a dummy round, a 123gn amax touches the lands at 2.212"

2.212 + 0.035 would put you at ~2.247, which is the approximate COL of factory Amax. I think another 0.010 to 0.015 to keep factory ammo out of the lands would be ideal. The 123gr Amax doesn't seem to mind a jump.

I have an older cut-rifled Satern where the 123gr Amax is touching the lands at ~2.262, which has worked very well with ~2.250 COL.