Machining an AR15 lower receiver

[Highpower]

(06-21-2012, 10:17 PM)TomG Wrote: Excellent work Willie, you should be very proud of it.

And thanks a bunch for taking the time to put together the build thread. I'm sure it will be well utilized.

It seems that I remember something about some issues with the hard coat job. How did that all work out?

Tom

Thank you Tom. Yes, I still believe anodizer overshot the current on their set-up or left them in the tank too long, or something. I own 4 different brands of AR's now and this is the only one I have ever had the surface layer pop off like it does.

There may have been a slight improvement after I have wiped down the surface with oil a few times now, but I can still get flakes if it gets bumped against anything. After test firing the gun a few times checking it for function (100% BTW... ) I noticed that I was loosing the finish on the extension lug.


That turned out to be caused from the rear of the rimfire bolt conversion rail. There is just the slightest gap at the rear of the upper receiver that allows the rail to move back and tap the extension lug during recoil, and pop off the anodizing.


So now I have turned a piece of Delrin about 1-1/2 inches long and put a short taper on the end, and stuck it inside the buffer tube. (See pic above.) Hopefully this will keep enough pressure on the rear of the conversion rail to keep it from moving back with every shot.

I'll just need to keep a bottle of Aluminum Black on hand to touch up the spots as they occur. Nothing else I can do I'm afraid.