I don't like roll pins on AR lowers so I will use the appropriate tap drill and tap for the 6-32 pins that Aero Precision provides for their M4E1 lowers. This tap allows you to reach behind the rear lower for full rotation and better alignment. I've used it at least half a dozen times and still sharp; I use cutting lubricant even though it cuts aluminum like butter. I cut almost all the way and use the screw to swage the last thread or two for a tight fit.
Rating:
[5 of 5 Stars!]