View Full Version : rethread onyx receiver

hammer of thor
July 22, 2007, 08:21
I have an onyx receiver that i am sure is bored at an angle, the barrel is 1/4 inch off to the left. I at first i thought it was timing, but now i'm sure it's not. Can the receiver be repaired or not? The threads on barrel and receiver are in great shape in and of themselves. It's just that the barrel is screwing in at an angle.

July 22, 2007, 10:40
A very unusual problem. According to the guy who used to own Onyx Arms, there were some "forgeries" of Onyx receivers made, so this may be one of them. If you want to "fix" it, the cost would probably be prohibitive, but here is a way to to it. The tool needed is a CNC thread-miller. This milling machine uses a rotary thread milling tool to cut the female (or male) thread form into a stationary part. That way, it isn't necessary to try to chuck up the receiver, properly aligned, into a lathe chuck and attempt to re-cut the threads. The sequence would be to bore out the existing threads with the same tool and then re-thread with a fine-pitch thread of your choosing - probably 20-28 TPI.
Then using a lathe, take a receiver stub (not too hard to find these days) and screw it on to your barrel breech with a "Inch pattern" breeching washer. The purpose of this will become obvious later. Secure it with blue locktite so you can get it off, but so that it won't move while you are working on it. Then place your barrel between centers on a lathe and turn down the receiver stub to the point where you can thread it with the same fine pitch thread form and dimension that will match those "milled" into the receiver. Remove the newly created threaded bushing and oil it with a heavy oil and screw it back on to the barrel breech threads, leaving it short of the barrel flange about .050" Then try fit it into the receiver. It won't likely "time" because the new fine pitch threads won't be "timed". But if you shift the bushing a little to the rear and re-check, eventually you will get it to "time", and then you can just torque it on.
If there is not enough meat in the receiver to do this, you can screw an old barrel stub into the receiver, securing it with red loc-tite and re-bore it smaller and then turn your good barrel down to a smaller thread form to match the smaller hole. Not as easy to adjust the pitch here and you may have difficulty "timing" the barrel. Not sure this is worth the trouble.

July 22, 2007, 10:56
interested in getting rid of it? personally i would build a plug. weld it in. drill the hole out and retap and be done. did this on a hesse gas tube hole

hammer of thor
July 22, 2007, 13:08
What can you tell me about onyx forgeries and how to contact the owner? And about what would this cost to plug the barrel and start over? THANKS! for input

July 22, 2007, 13:16
got square ???...1st id see where its out ......if the end of the muzzle is .250 out ...checking the reciever face for perp in relation to the sides of the receiver with a mach square will be obvious ....
if the face is out ..put it in the mill dial in the sides and the top rails ..remill the face for clean up and look for a spacer to headspace it ....but only if the deviation is limited as your thread slop will have to take up the correction ...lots of lock tite .he he ...wont be a sniper ...but it should blow the hell out of a 82 buick ......dont be a wescogger ..find the problem before youget out the hacksaw and the welder ..he he .....

July 22, 2007, 13:26
Here's the member "Onyx Arms" profile...


...and here are all his posts.


He's into Land Rover's now... http://www.roverpartsused.com/

hammer of thor
July 22, 2007, 16:31
Thanks for the info, from what iv'e read, this onyx receiver is not proofmarked and could be dangerous. The whole thing is that their is such a great rifle set built on this problem receiver, i'm not sure if the receiver is any good. Best bet would be to buy a new receiver and not worry about it anymore. thanks again for info, been great help to me.

July 22, 2007, 22:47
hammer of thor, let me know if you wanna get rid of the reciever, i will plug the hole, weld it in, retap it and make a 22 hornet, or 22 mag 7.62 x39, or something else bad ass on it. trouble recievers are no trouble for me.