Gunsmithing Update on rough bore-AR

[downhill]

Back in Aug. I posted a problem with a SS 1/8 AR Bbl. It would not group under 4"@ 200yds and would really tear up a patch when cleaning. I happened to run into a shooter who owns a borescope. It turned out that the chamber went right into rifling--No throat or freebore at all. I went ahead and had it throated for SMK 77's,now she holds a honest 1 1/2" @200. The Bbl has no manufacturer stamp and I don't remember it's origin(trade,gunshow,I have too much stuff-don't know).Anyway maybe this will help someone else in the future.

 

[Hellbender]

Re: Update on rough bore-AR

I've seen CMMG barrels like that, they pawn them off at the gunshows. It would ruin a brass brush in a few strokes.

We sent one back to them and they returned it and said it was all "mil-spec", the inside of the upper receiver was so rough it looked like a wood rasp. My buddy still has it, I think he made a lamp or something out of it.