close a bolt face

[medhist]

I had a rifle barreled in a rimmed caliber. THe smith opened the bolt face to accomodate it. Is there any way to return the bolt face to the rimless diameter as I plan on having the barrel rebored from its present obsolete caliber. THis is an Inrtarms Mk X action with a bull barrel so its basically a Mauser 98 .Many thanks.

 

[kendog]

I had a rifle barreled in a rimmed caliber. THe smith opened the bolt face to accomodate it. Is there any way to return the bolt face to the rimless diameter as I plan on having the barrel rebored from its present obsolete caliber. Many thanks.

There is just about nothing that time or money wont fix. Sometimes LOTS of each.
A little more detail would be nice. Action, caliber(s) etc.

 

[Preacher]

Not a problem at all, just bush the bolt face...

 

[jfseaman]

Not a problem at all, just bush the bolt face...

I would like to do this for an odd size cartridge.

By "bush the bolt face" do you mean?

Disassemble the bolt.
Ensure the bold face is true to the bolt and recess.
Turn a bushing to match the ID of the bolt face. +.0005 -.000, The OD of the case +.002
Protect the firing pin and ejector hole with ceramic clay/heat stop.
Clean the bolt surface scrupulously in preparation for silver soldering.
Paint the bolt surface carefully with silver solder flux or paste.
Paint the bushing with silver solder paste.
Insert/press the bushing into the bolt nose.
Paint/cover the bolt from just below the nose with heat stop.
Heat the bolt nose to the temperature needed to melt and flow the silver solder.
Remove all the heat stop and clean the bolt.
Clean up any leaked/flowed silver solder from the bolt nose, firing pin hole, ejector hold.
Machine the extractor groove.
Install and test the new extractor that matches the cartridge.
Install the firing pin, ejector, etc...

Thoot 'em.

 

[medhist]

There is just about nothing that time or money wont fix. Sometimes LOTS of each.
A little more detail would be nice. Action, caliber(s) etc.

It was originally a 25-35 case rim. I want to go to .308 Win.

 

[Preacher]

I would like to do this for an odd size cartridge.

By "bush the bolt face" do you mean?

Disassemble the bolt.
Ensure the bold face is true to the bolt and recess.
Turn a bushing to match the ID of the bolt face. +.0005 -.000, The OD of the case +.002
Protect the firing pin and ejector hole with ceramic clay/heat stop.
Clean the bolt surface scrupulously in preparation for silver soldering.
Paint the bolt surface carefully with silver solder flux or paste.
Paint the bushing with silver solder paste.
Insert/press the bushing into the bolt nose.
Paint/cover the bolt from just below the nose with heat stop.
Heat the bolt nose to the temperature needed to melt and flow the silver solder.
Remove all the heat stop and clean the bolt.
Clean up any leaked/flowed silver solder from the bolt nose, firing pin hole, ejector hold.
Machine the extractor groove.
Install and test the new extractor that matches the cartridge.
Install the firing pin, ejector, etc...

Thoot 'em.

That sure should do it up as good as it will get....

 

[shortgrass]

The Hi Force 44 solder, that Brownells sells, works just fine. Flows at under 500*F, no worries about over heating the bolt head that way, unless you just go crazy with the heat source you're using. A slight groove on the outside of the bushing and matching groove where the bushing will sit will make for a good mechanical lock if you do a good job of soldering. You would want a press fit if you were to weld, but soldering is adhesion, so a very slight gap (.001-.002") to fill with solder is desirable. Leave the bushing under sized in its bore, and open to size after the bushing is securely soldered in.

 

[jfseaman]

Thank you @shortgrass !

I know it was @medhist 's question originally but I have been wondering and working on how to do it. Haven't done it yet.

Modify line 2 to be -.001 to -.002 and the ID of the bushing +.010 or more of the case. So for a 308, the base is .473 the bolt ID is usually what, .0478? So leave the ID of the bushing around .460?

I like what you said about a .001 groove in the OD of the bushing to make a mechanical bond.

Thank you for the info on Force 44 Solder. I wonder if I can get an induction coil to do it so as to not spread the heat to much. That do you think of that rather than a flame?

 

[Will Henry]

This is not a recessed boltface like a Remington; it's a Mauser. The cartridge is not fully enclosed.One could solder a bushing into the face then cut through where required. One could also TIG the periphery of the face and re-cut. If it was mine, I would go to a gunshow and pick up any model 98 bolt body for about twenty bucks, weld on a new handle, and put the bolt into the MkX receiver. WH

 

[shortgrass]

True welding is melting two or more pieces together, so tigging up the bolt face is a no-no, 'cause that's hot enough to destroy the temper. I'd order up another bolt, but a good '98 bolt ain't $20 anymore. Even considering the cost of welding on another handle it'd be a darned site cheaper and a better fix than any other I can think of. Occasionally, you'll find a MK X bolt on GunBroker. The 'guts' out of that MK X bolt will fit and work in a military '98 bolt, you'll need a different extractor, too. Nice the OP decided to provide more info............

 

[Will Henry]

With a good heat sink (I like aluminum), welding up a Mauser can be done with no consequences. I have done this. Of course, this is dependent upon the metallurgy of the bolt. A 98 is low-carbon steel which is selectively case-hardened. I believe the Interarms bolt may be an alloy in which case the issues regarding heat treatment and welding are a little different. WH

 

[swd]

This is a no brainer for a 98, get another bolt. Cheap and abundant.