Angle for cone breach to do away with extractor grove

[macca81]

Can anyone start me on the right track, i would like to cut a cone breach on chamber-end of next barrel for my walther bench gun to do away with grinding extractor groves & be able to turn barrel to different indexing marks for ammo testing. Anyone know what angle i should use for cone?

 

[holstil]

I'm guessing it would have to be similar to what the extraction cut is? You got me curious, it is cut at an angle? The extractor would tell you what angle it would have to be. I'm gonna have to look in the morning. I'll put my lil angle gage on it tomorrow.
Let me know about your testing please. Maybe turning some barrels this week
Jim

 

[macca81]

Have been looking around & came across some pictures of a cone breech being cut with a radius tool. To give a sloping radius instead of a straight cut cone.

 

[msnations]

I use a 1/2" ball end mill to cut the breech. For an anschutz I just cut .4" into the breech face, and deep enough to reach the chamber lead radius...

-Mark