Custom Barrel Nut needed for Armalite AR-10

So I'm working on a retro project that involves an AR-10A2 Carbine upper receiver. I bought the upper used and complete, and it came with midlength handguards and Armalite spec midlength gas system.

I set out to rebarrel it with a midlength gas system DPMS spec barrel made by Ballistic Advantage, and a DPMS spec BCG from Brownells. All gravy so far.

When I went to put everything back together, I ran into a problem that took me a couple of days to figure out. The handguards wouldn't fit between the handguard retainer cap and the delta ring. I compared them against 4 different drop in midlength handguards from as many different manufacturers, and they were all the same size. Everything else was where it should be and fit together fine. What the hell was the problem?

Turns out the Armalite barrel nuts not only have a proprietary thread pitch (Armalite is 1-7/16"-18, DPMS is 1-7/16"-16, which is why I intended to reuse the Armalite barrel nut assembly,) but they're LONGER than DPMS spec barrel nuts by just long enough to be a pain in the ass.

Long story short, I need a 308 size DPMS length barrel nut for a delta ring and drop in handguards, with the Armalite thread pitch (1-7/16"-18) inside.

I was referred to this place by a machinist friend in the industry to find a small shop that could make the barrel nut for me. I only need the one. Is there anyone here that can help me with this?

I made a "custom" barrel nut for a DPMS 308 "minimalist" build.

Done in SS, it takes a long time to put in all those holes with the work on a dividing head. They are >10x depth to diameter. Fussy work ....

I'm betting the cost exceeds the value .......unless you DIY.

I'm not even remotely a machinist. If I could find a DPMS 308 sized barrel nut without threading and turn it over to someone for threading, I would have much rather done that, but alas, I've no such luck.

How much would it cost?

SnakeX13D said:

Turns out the Armalite barrel nuts not only have a proprietary thread pitch (Armalite is 1-7/16"-18, DPMS is 1-7/16"-16, which is why I intended to reuse the Armalite barrel nut assembly,) but they're LONGER than DPMS spec barrel nuts by just long enough to be a pain in the ass.

Long story short, I need a 308 size DPMS length barrel nut for a delta ring and drop in handguards, with the Armalite thread pitch (1-7/16"-18) inside.

Click to expand...

If the one you have is just to long, can it be shortened? A lot easier to do do that than make one from scratch.

Rob F. said:

If the one you have is just to long, can it be shortened? A lot easier to do do that than make one from scratch.

Click to expand...

Nope. We thought of that already. It indexes off the barrel extension flange at the same point regardless of how long it is in the back. It's the front that's too long, in the neck, if that makes sense.

Long story short, I need one of these in the aforementioned thread pitch (1-7/16"-18)

DPMS AR .308 BARREL NUT | Brownells

Turns out the problem is not the barrel nut.

So what was it?

Your answer might help others.