Bolt lapping

[cst]

So polishing with a dremel is useless...all ur doing is rrmoving the finish...and if ur doing too much youll screw the face then? Because there is no way ur gonna be able to truly square it by hand.......

[Tedward]

If you think about it the bolt was made and turned on a lathe. It is more true than anything you will do to it. I would leave it alone and let the surfaces wear together. The bolt has play to begin with since it is a AR-15 and semi-auto setup so the ammo can feed. On a bolt gum, you might see a difference but that is usually done with some precise measuring and a person who has done it a few times and practice makes perfection..

[LRRPF52]

A buddy of mine who is an OCD engineer, attended two different gunsmithing schools during his vacation time while pursuing his engineering degree. He is one of the few people that can crack the code on working with a certain advanced alloy developed by the Naval Ordnance Laboratory back in the 1950's that is also used in the medical device industry, and he does a lot of prototype work in that field.

He's a very attention-to-detail type of person, with a great understanding of materials, metallurgy, assembly methods, and does all kinds of accuracy tweaks on his rifles that he learned in the gunsmithing courses.

On his Armalite .260 Rem, he polished the bolt face, took the edges off the lugs, slightly chamfered the firing pin and ejector holes, took the edge off the extractor shelf/bolt face junction, tuned the extractor, lapped the lugs, and polished the snot out of his bolt face with a Dremel tool.

It was night and day difference in his brass condition before and after. Factory ammo and his initial hand loads showed pretty rough abuse of the brass, with ejector channel shadow and shearing of brass, rings from the firing pin hole, and case rim damage. Accuracy was erratic with all the factory ammo, but he had a feeling there was potential in the gun.

His brass now looks pristine upon ejection, and he's getting 5 rounds under 1.5" at 300yds with the 142gr SMK at 2740fps from a 22" Armalite AR10. He does the same things on bolt guns, and you basically can't miss with his rifles unless you really try. It's just something he really loves to do on the side. He takes "accuracy nazi" to a whole new level when he does load development with the ladder-testing method at 500yds.

When other gunsmiths look at his thread work, they ask if it was done on a CNC, and when he tells them it was done by hand on a lathe, they call BS. He'll let the lathe indicate on a gauge for 45 minutes before he even thinks about chucking up a barrel. He orders American-made mills and lathes from the 1940's, completely strips them down, detail-cleans them, and rebuilds them before he even considers using them. He's a very interesting and knowledgeable guy when it comes to materials science, and how that translates into making an accurate rifle.

For the rifles I have, I'll be tapping into his recommendations because the groups, pristine brass condition, and low ES don't lie.