I have a good bit of experience threading and chambering barrels for custom benchrest actions and Remingtons but have never barreled a pre 64 or a Mauser. I want to get a Monatna Action and need to know how to set up the barrel. Should the face of the tennon and the barrel shoulder make contact at the same time or should the tennon face be a couple of thousands short when the barrel shoulder hits the receiver face..

No extractor cut??
Thanks for any help.

Rancher,

I believe in load sharing. I set these up so they make contact at the same time.

Malm

Rancher---

The inner ring of the Montana 1999 action is machined true with the bore along with the receiver face.......well done, too.

I'd cut the barrel to contact at the same time just like a Mauser.

The neat thing about the Montana is that the inner ring is shaped like a M-70 at the rear and the hole in the middle is smaller than the bolt. VERY strong and should feed like a gut pile through an ice hole.

So the shank of the barrel is flat-faced like a M-98 with .120 more length of thread but when installed and viewed from the rear it looks just like a M-70.........

Hey Rod-- Did ya'll get that from Charlie Newton?

The problem that you get into with the Mauser-type breeching is the fact that you have two potential surfaces that can make contact, but only one will be the primary locator. Typically what we do is set the barrel length to the inner ring and allow .001-.002 MAX clearance on the front of the receiver. You can never get both surfaces to make equal contact for the fact that they reside in the same plane, so you should pick one that's closest to the bolt, that being the inner ring, and let the other surface float. If you're getting both surfaces to make contact, you are causing a conflict between the two surfaces. As a result, one surface of the receiver will have to be distorted in order to make contact with other simultaniously. This can be easily done considering that your working with one of the most powerful forces on earth, the screw.

I have always cut the barrel tenon so it is .001" short of the measurement from the face to the collar. In the scheme of things .001 is nothing but I definitely want primary contact at the faceof the receiver. Under torque the barrel will end up contacting solidly at both locations. I have always felt the shoulder of the barrel to be somewhat more compressible than the breech end. Ending up with clearance at the shoulder results in a less rigid unit. Regards, Bill.

I gotta do better searches on this forum. Missed this thread. Forgive my earlier post, Rancher. Didn't know you planned on the installation yourself.

Jack, that breeching system was one of the few home grown ideas that stuck. Not to say someone else didn't think of it first, but if so, we hadn't heard of it. It was sort of a "What if?" What if we sliced the back end off a M70 barrel like a slice of baloney and made it part of the receiver by casting it in place. Then screwing the "sliced-off" barrel back in place. Receiver is stronger and barrel much easier to make.

And so far, feeding has been good. (I like your description much better.)

We fooled around with a lot of crazy ideas back in the days before we had money to make mistakes in steel. One was a reverse taper on the front side of the Mauser ring, making a self-centering breech on the barrel. Could probably get the the breeching clearance down to about .075 with that one.