07-18-2020, 01:15 PM
I have the same Stoner lap tool & it fits in some uppers but not in others. Some uppers have tighter than mil-spec bores. A lapping tool manufactured for mil-spec uppers isn't gonna work. Turning it down is an option I suppose. If mine doesn't fit, I bypass the lapping step.
I refuse to be victimized by notions of virtuous behavior.