Rebarreling and Threading a Mini 14

[Vernonia MW]

Hello NWFA!

A little while back, I took on the project of rebarreling and threading a Mini 14. I see no good resources documenting how this is done, so I figured I would post up my process on how I did it. This could very easily be a skinned cat situation.

A customer brought in a 186 series Mini 14, and was wanting the current barrel exchanged for a take-off barrel that was purchased from a third party. He also wanted the muzzle threaded for a flash hider. I unthreaded the factory barrel and hand tightened the new replacement. The first picture shows the original barrel at hand tight. The flat with the "W" engraved on it clocks at 5 o'clock. Once torqued, the flat will be at 6 o'clock. The second picture shows how far off from clocking the new barrel is (sorry for the bad angle, the barrel was mounted in my lathe for this pic). It was clocking closer to 4 o'clock.

I have seen some confusion about this online. It would appear that unlike the M1 Garand/M14 series, Ruger does not control the timing of their threads to ensure proper barrel installation. They must use other methods. If I were to guess, it has to do with the numbers/letters engraved on the aforementioned flat.

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[Vernonia MW]

Following my normal process, I indicated in the barrel on the Prototrak. I wrote up a program that would recontour the entire face of the barrel. It was actually a fairly complex geometry to match, so I was glad I had the CNC capability to do this. On the manual lathe would have been a little tedious. I then took off equal amounts of material from the barrel face and shoulder.

The pictures show the process and the end result, with the barrel installed and torqued, and the flat properly lined up at 6 o'clock. Note: in this case, I did not have to mess with the extractor relief.

 

[Vernonia MW]

In order to thread the muzzle, I re-mounted and re-indicated the barrel in the lathe. Threading went off without a hitch. There is not really enough barrel diameter for a proper shoulder, so they are really only good for a muzzle brake/flash hider. Running a suppressor could be done, but alignment would need to be checked and monitored closely. This was a rare case where adding a thread collar was discussed and ultimately decided against.

At this point, the barrel was almost ready. Headspace was checked and, as expected, found to be short. A pull through .223 Wylde reamer was then used to get the bolt to close on the go gauge.

And here is the complete rifle. Nothing else needed to be done to account for the shortening of the barrel. I was worried that parts of the gas system would need to be attended to. This turned out to not be the case. The next one of these that I do, I would just re-chamber in the lathe. And, to those who were curious, the new barrel shot just as poorly as the old barrel. We were hoping for a better outcome on that front.

 

[Knobgoblin]

Sticking with the factory blade front sight seems like a missed opportunity for some cosmetic improvement.
Sucks about the accuracy. But not a shock for anyone, I'm sure.

Dig that hogue ghillie stock.