Not Too long ago I have witnessed Several uppers that are take offs from rebuilt M16A1 rifles staying marketed as "new substitution uppers". I have noticed great effects with electroetching. It does choose some apply to get the depth uniform. I believe the stencils are just one time use so https://titushhgcy.mybloglicious.com/51947300/the-basic-principles-of-gold-cup-trophy-colt-45