Richardson Receiver Barrel Threads Tight

[H2munitions]

I'm working on installing a barrel into my Richardson ultimax receiver. All of the USGI guns I've worked on I could easily thread on the barrel by hand and torque with a wrench the last 1/4-1/8 turn. 

 

On the Richardson I can only get the barrel started about a couple threads and it gets very tight. There is no thread damage on either peice and I tried different barrels. Reading up the min/major thread call out I did confirm the threads are in spec on the barrels. From the measurements I can take it appears there is about 5 thou of extra material in the grooves of the threads. 

 

I guess I'll have to put a barrel in the lathe and make light passes until it threads on the receiver. 

 

Anyone else run into this before?

Edited Tuesday at 01:50 PM by H2munitions

[reconbob]

   I have never had a problem with a Richardson receiver, but in my travels I have encountered this problem - usually with aftermarket barrels. The thing to do would be to put the barrel in a  lathe and file the thread major with a flat file at low RPMs. This should enable the barrel to turn on a couple more turns. If you get the barrel to screw in 1/2 way I would use fine-to-medium valve grinding compound. Hold the barrel in a padded vise. Put a generous amount on the barrel threads and screw the receiver onto the barrel. When it won't turn any more use a cutoff broom handle or similar piece of wood that will not mar the receiver and use it as a handle to turn on/turn off, turn on/turn off the receiver onto the barrel. You will see that the barrel will turn on a little farther each time. If needed apply more compound to the threads. You should be able to get the barrel to turn all the way on in a few minutes. Once the barrel hits the shoulder of the receiver you're finished. Clean all the compound out of the receiver and off the barrel threads and you are all set. Only 0.001" can be enough extra material either on the barrel or the receiver to make a barrel too tight to screw on. While this may not seem like a precision approach, I have used it dozens of times over the years and it does no harm to the receiver or the barrel. The only "damage" is the bluing will be rubbed off the receiver and barrel threads, but when the barrel is fitted you can't see this and there is no danger of corrosion.

Bob

Edited Wednesday at 02:38 AM by reconbob