Mauser Rebarrel - Part 4, Extractor Cut

[Clemson]

The final phase in rebarreling the M48 is cutting the extractor slot. This can be done in a number of ways, varying from hand files to CNC machines. The approach shown here is only one of them.

 

In actual fact, the easiest way to do this has to be with a milling attachment on a lathe. An end mill is held in the collet chuck, the barrel is held in the milling attachment vise, and the whole works is traversed by the end mill to cut the required slot. From the looks of the cut on the take-off military barrel, the Yugoslavs used an end mill to cut the original extractor slot.

 

Unfortunately, I don't have a milling attachment.

 

I reinstalled the barrel in the receiver and marked the position of the extractor cut using a long scribe through the rear of the receiver. I took the barrel back off and mounted it in a vise on the table of the milling machine as shown:

 

I am using a 1" x 5/16" keyseat cutter to cut the slot. It made a wonderfully smooth cut, as you can see. I had to make two passes to get the full width of the slot cut, taking out the scribed lines on the top and the bottom. The cut goes through the boss and also about .025 deep into the torque shoulder.

 

Here is the finished cut, with some of the Dykem still showing on the boss. This cut gives the extractor plenty of room to grab the rim of the cartridge without danger of binding.

 

Clemson

[Manitou]

Clemson,

Thanks for this tutorial. I've rebarreled 5 Swedes (All with surplus, new barrels from Samco), put a surplus Swede barrel on a Turk, and an Adams and Bennett barrel (6.5x55 rethreaded) on a Turk. Now I'm putting two 7mm-08 Rem take-offs on the last of my Turks. I have never had to do the extractor cut, but may in the future if I can get an M48 to work on.

Your pictures were clear and instruction were easy to understand. Thanks.

Manitou

[ken98k]

Clemson,

When clamping the barrel, how do you determine if the breach face is perpendicular to your mill?

Kenny

[Clemson]

Clemson,

When clamping the barrel, how do you determine if the breach face is perpendicular to your mill?

Kenny

 

Good question. There are a bunch of ways to do it, some a lot more scientific than the method that I used. I set up the vise parallel to the milling table, and trammed the table back and forth to insure that it was parallel. The vise has a grooved jaw that I clamped the parallel portion of the barrel shank in. I simply assumed that the v-groove in the jaw was parallel to the table and perpendicular to the cutter. For cutting an extractor relief groove, that is accuracy enough. You will note in the photos some scraps of paper on one side of the mill and also a flashlight on the other side. I use the paper between the cutter and the work, and feed the work into the cutter until the cutter grabs the paper. That tells me that I am less than .003" from the work. I can then set the depth of cut with some confidence. I moved the table up and down to just barely remove the scribed lines for the cut.

 

Clemson

[z1r]

Assuming a squzre breech then a machinist square is about the easiest way. Also, if the chamber area is parallel an indicator works well too.