[Redlg155]

I've posted the dissapointments that I had on initial firing of a CETME during a recent range session in the rifle forum.

Part of the problem was that there were burrs in the rifling on the lands just forward of the chamber. If you look down the bore they are very noticeable, one on each land. I think that the rifle may be salvageable without a rebarrel if I could remove these burrs. I had a failure to extract and partially popped primers when I attempted to fire the weapon. I believe this was due the a pressure spike created by the burrs when the bullet passed.

Anyone have an idea of how I could remove these burrs?

Good Shooting
Red

[Desert Dog]

J-B bore paste and a LOT of elbow grease...

[stevelyn]

You might try looking into fire lapping if you reload.

[Jim Watson]

If the burrs are at the very origin of the rifling, maybe thrown up by a bad chamber reamer, you could use a throating reamer ($28 from Brownell's) to advance the throat a fraction. It would form a little freebore which should not hurt accuracy or function.

I do have a hard time visualizing a burr bad enough to cause FTEx and blown primers, though. Maybe the chamber reamer was VERY bad and you need at least a sharp new reamer run in and headspace checked.

I am NRA Mechanically Inept and would seek my gunsmith in either case.

[Jim K]

I also can't imagine any way a burr in the rifling could raise pressure, though burrs or roughness in the chamber can lead to failure to extract. The first suspect would be the ammo; I had trouble with South African ammo not extracting in an FAL; polishing the chamber took care of the problem, which was apparently caused by soft brass.

I agree on fire lapping as the best way to get rid of burrs or roughness in the barrel. There is a kit available and finding someone to load a few rounds should be no problem.

Jim