SGM internal trunion mount?

[RGVBadBoy 9]

The thread on the tube and trunnion should be the same; mil spec or commercial. The different diameter they are referring to is the actual tube part that the stock slides onto. A commercial stock, will be lose on a mil spec tube, and a mil spec stock wont fit on a commercial tube.

 

So its either the trunnion's or tube's thread thats out of spec. I think its probably the later. Try a quality AR receiver extension (buffer tube) from VLTOR or LMT. A Stag, Spikes or CMMG will do too. Hope this helps.

 

 

I ended up ordering a 1 13/16" - 16 tpi AR receiver tap from Brownells http://www.brownells...VER_TAPS___DIES. The tap took quite a bit of material out of the trunnion. All of my buffer tubes (mil spec and comm. spec) now thread effortlessly. I also ground the bottom tab on the bottom of the trunnion flush to match the receiver. The trunnion buffer tube threads are definitely out of spec. So be aware that you will have to spend some extra cash on a tap or be creative and use a wire wheel like Plastik did above.

I just went with this, I needed that internal trunnion mount, it had the wrong thread, I ordered the tap, I can't wait till its here, gonna be awesome:)

[Goose 95]

Got mine in a few days ago and finally got it installed and everything back together. I'm running an ACE Socom stock and couldn't thread it past a about 1/4-1/2 inch or so. Could have been from the tough to get off thread locker, or from the marred threads that I screwed up last year... I was taking the pig nose off and completely forgot about the set screw on the under side. I felt like an idiot. Anyway I picked up a brush wheel for the power drill, cleaned off the thread locker and cleaned up the poor threads and she turned all the way in, very smoothly and yet no play or wiggle what so ever, I was pretty happy bout that.

 

Cutting the tab off and grinding it flush was easy enough. It completely ate away the off brand cutting wheel that came with my tool, but the Dremel brand wheel finished the job. For the issue with the bottom screw interfering with the SAW grip, I mocked up the grip and ran a 3/16 drill through the hole to mark my place. I then chewed a lil bit at a time with a 3/8 bit until the head of the screw would fit and be flush with the top of the grip.

 

The real bitch was installing the trunnion itself. I'd wondered how well a Russian stamped and riveted sheet of metal would pair up to an American CNC'd part, and I was right. I ended up taking the small, cone shaped, green stone in my rotary tool bits kit, and very carefully and slowly, taking away from the edge of the holes in the receiver that interupted the screwing threading in. I probably could have taken more, as a couple of the screws almost felt cross threaded when I finished up, but I'd rather it be too tight than too loose (knock on wood).

 

Turned the castle nut all the way to the rear, turned the stock all the way to the castle nut, and only needed to go back about 1/32 of an inch to be able to thread the set screw in properly. Cranked down on the castle nut and put the rest of her guts back in. Took an inch off the LOP, I'm more confident about the strength, and looks a lot cleaner.

 

Then I went to fix the dishwasher and got water all over the floor...

 

P.S.- I also went ahead and took off the side rail, it's going to make a great bottle opener

Edited September 13, 2012 by Goose

[jcarter1974 5]

Take a look at the new Rifle Dynamics AK to M4 stock adaptor review I did.

 

http://forum.saiga-12.com/index.php?/topic/80317-rifle-dynamics-m4-stock-adaptor-rdak-m-4/

[Goose 95]

Interesting design, pretty inovative I like it. I'll still keep the SGM though, it's a simpler with less joints, shorter LOP and my sights aren't gonna be high enough for the Rifle Dynamics cheek weld.

 

But again, that's pretty damn cool. If you were gonna do a Choas rail with the full length, dust cover-cover, it would be pretty hot

[RGVBadBoy 9]

Goose, are you using a mil-spec tube or commercial?

 

I ordered the tap to rethread the SGM if need be, I don't need to, great, but I build a lot of AR rifles and its a tool i needed anyway.

 

Thanks,

 

Mike

[Goose 95]

Well, that's why I made sure I could clean the threads and make it fit before I cut the trunnion. I didn't find which one it is, but the ACE Socom stock comes with it's own special tube. I'm not sayin I hunkered and spend a lot of time tryin to figure it out or anything, but it's an ACE Socom stock.

Edited September 16, 2012 by Goose

[RGVBadBoy 9]

UPDATE: The SGM Tactical trunnion showed up today and the Nordic Components CRS I plan on using threaded perfectly into it, looks like I won't be needed to tap the SGM trunnion after all:) I'll get pics up ASAP:) I'm hoping to work on it tomorrow.