Erma E M1 Carbine front sight

[Sentryduty]

In other words, a chamfer will still cause some shaving if it has a sharp edge. The edge must be rounded.

The real problem is: How can one achieve this without FUBARing the rifle????

Would it be possible to get a dremel rotary tool with a 90 degree attachment into the chamber? If so, I would start with a conical felt polishing bob and a compound, finishing with a polish, it should round the chamber lip very slowly without resorting to possibly ruinous bit based grinding.

I had a Norinco Type-97 NSR that needed the feed ramp reprofiled to run with non-Norinco magazines and undertook a similar smoothing process. The Norinco magazine fit tightly in the magazine housing and the rounds made a smooth jump to the chamber. Non-Norinco magazines would rock fore and aft which changed the presentation of the next round, often tipping into the feed ramp and ramming the projectile well into the case with extreme force. In my case I started with jeweler hand files and finished with Dremel felt polishing.