Mauser Rebarrel - Part 3, Hand Reaming

[Clemson]

I stopped exactly 0.0015" short of full depth in the lathe. The next step requires the barrel to be reinstalled on the receiver. I use pine rosin on the barrel vise blocks and lean on the receiver with a sturdy action wrench.

 

I always use a bit of high-pressure grease on the threads. It doesn't need to be anything high-tech -- this is ordinary wheel bearing grease.

 

I like to do hand-reaming on a vertical barrel. This is certainly not essential, but it helps to insure that you don't over-cut one side of the chamber. In order to hold the barrel, I am using a smaller barrel vise that I made from one-inch steel with some handmade aluminum bushings. I swing this vise sideways in the benchvise to hold the barreled action vertical. This bench vise is an old Versa-vise that I bought in an Ebay auction. What a gem it is! You can use it in either a vertical or horizontal plane.

 

I turn the reamer with a large tap wrench, using lots of cutting fluid. I switched to Rapid Tap for this last part. No particular reason for that, as the Nuclear Cutting Oil would have worked fine; it's just personal preference.

 

Make only a couple of turns at a time before checking chamber depth. Clean the chamber using compressed air if you have it....

 

And also use a pistol rod with a patch on it....

 

The important thing is to insure that the chamber is squeaky-clean. Insert the go gauge into the chamber, and then put the stripped bolt into the receiver and try to close it.

 

For a standard breech, I have used a bolt with the extractor still attached. In the case of the safety breech, we have not yet cut the extractor slot, so we have to use a stripped bolt. Also, be sure to remove the extractor collar. Otherwise it can turn cattywhompus (engineering technical term learned at Clemson) inside the receiver and bind up the works. It is probably good practice just to strip the bolt for each chamber job regardless. You then have to "pick" the "Go" gauge out of the chamber after measuring, but that is fairly simple. I used a bent scribe that you can see lying on top of the extractor to the right of the vise.

 

Cut the chamber until the bolt will close with slight drag on the "Go" Gauge.

 

After you cut the chamber, you MUST clean the cutting oil off your tools and out of your barrel, and oil the reamer, gauges, and barrel. I just spray them with RemOil that I keep on the bench. The cutting oils have no rust protection built in, and you will ruin your tools if you do not clean and oil them after cutting a chamber.

 

This last shot shows the reason for cutting a safety breech. No, it is not absolutely necessary, but this shot shows the "Go" gauge seated in the breech of the barrel after the chamber has been cut. There is only 0.050" exposed. It really was not a great deal more effort to cut the safety breech, either.

 

Lastly, we will cut the extractor slot.

 

Clemson

[Doble Troble]

Really nice documentation, Clemson. This is archive material. Looking forward to the next installment!