40x coned breach

[kasjaka]

anyone have any advise reguarding pros and cons of a coned breach
when barreling a 40x rimfire as opposed to extractor cuts?????
thanks
scott

 

[Fred J]

Several do it

Several very good smith's do this, and I haven't seen any problems with it. I sa w 40X yesterday that just came back from an excellent smith. I feel it's advantagous, as you don't get the heavy way build up between the bolt face and the breech.

 

[crb]

I don't like the 'sharp' edge to ends up being the anvil the firing pin force is exerted onto. Both of my current RF bbls have a cone breech as I didn't have a milling machine when I did them. If I ever rechamber them I will probably do a partial cone leaving a large flat area at the 12 o'clock section of the breech.

I have one bbl set up with a pacnor nut and it is nice to have the room to adjust the headspace if you feel the need.

 

[Mad`]

I had a coned breech on a Time. The cone would crack on the far side of the cone. It happened to a Shilen barrel and a Lilja barrel. I suspect it cracked because it was so thin and the pressure from the extractor to snap over the rim of the brass was the culprit. I had two well known gunsmiths on this board have a shot at it to no avail. One of them repaired it three times on the same barrel. It was a sweet shooting rifle, I did really well with it, but when the crack started it wouldn't shoot straight.
I gave up and sold it. The new owner knows the issue.
It's not cracked right now but I never shot it after the last repair. The new owner hasn't shot the rifle yet because of the weather.
I wouldn't have another coned breech ever again.