AAC QD suppressor upgrade

[MCMXI]

I have four AAC rifle suppressors including an M4-2000 and 762-SDN-6 that use the 51T interface. I also have the MK13-SD and TiTAN-QD that use the 90T interface. They're very good suppressors in terms of noise reduction, durability and precision, but the interface is marginal due to the inability to keep the suppressor tightly connected to the rifle. A coworker managed to send his 762-SDN-6 downrange last year due to it working loose. I have a number of Dead Air suppressors that have an excellent QD interface (best I've used) and have a couple of SilencerCo suppressors that use what I would describe as an improved version of the AAC system.

This week I sent off the M4-200 to be modified to my specifications. I created models and drawings of the AAC products I have and came up with a better interface that gives the owner a number of good options. I won't say much more about this until the M4-2000 is back and I've had a chance to test it, but if all goes as planned I expect to be able to talk about a significant upgrade to AAC suppressors that use the 51T and 90T interface. My priority is to fix the four products I have so that I enjoy using them, but I've also thought about offering an upgrade service if all goes to plan.

 

[Ryanxia]

Curious to learn more. I have the 762-SDN-6.

 

[MCMXI]

The machine shop called me yesterday and I had a brief discussion with a manager and machinist and we all seem to be on the same page. Hopefully I'll have something to talk about next week. This could be epic or an epic fail.

 

[MCMXI]

I got the M4-2000 back from the machine shop today and need to evaluate various aspects of the modification but it shows promise. You can see in the photo below that the modification involves removing AAC's crappy interface to make way for various SilencerCo and Dead Air Armament attachment options. The photo below shows the M4-2000 with SilencerCo's Omega direct thread adapter and ASR mount as well as Dead Air Armaments's KEY-MO adapter that interfaces with their KEYMOUNT muzzle brake (my preferred QD system).

The machine shop marred the paint finish in a number of places but I can easily reapply Cerakote if necessary. They did a good job on the threads that I requested and concentricity looks good but I'd need a CMM or other way to obtain accurate measurements to say anything definitive about the alignment of the new threads to the bores in the baffles and end cap. I need to make a small modification to allow the direct thread adapter shoulder to fully seat against the outer tube of the suppressor, but both of the brake adapters fully seat against the outer tube. At this stage I don't really see this as being commercially viable due to the cost of the upgrade. I had the machine shop sign an NDA with the idea that I could offer this service to other AAC owners. It's worth it to me since I'm a picky bastard but I don't see many willing to pay out for the machining and mounting accessories, but you never know. I'm going to send my three other suppressors out for the modification because I have too much money tied up in them not to want to use them.

I'd be interested in hearing any feedback re this upgrade and I'll report back once I've had a chance to shoot the M4-2000.

 

[MCMXI]

I checked the fit of the modified M4-2000 and KEY-MO adapter on the KEYMOUNT brake that's currently on one of my machine guns and ran a magazine through without any issues. The can got very hot as usual but nothing weird to report. Accuracy was as good as always and I think that the M4-2000 has found a permanent home. One down, three to go.

 

[MCMXI]

UPDATE: I (and others) have put 500 or so rounds through the modified AAC M42000 without any issues. It's screwed on to a Dead Air KEY-MO adapter without any Rocksett on the threads. I was easily able to unscrew the main tube off the adapter even when the can was very hot but it didn't shoot loose. I'm really pleased with how this has turned out and feel that this is a good upgrade over AAC's crappy mounting system. I have a conference call next week with the company that did the work and will definitely be sending my other three AAC QD cans to them for the same modification. I think they did a great job maintaining concentricity of the new threads to the bore of the baffles, based on no issues over 500 rounds. My plan at this stage is to offer this upgrade to anyone that's interested and I'll have some firm pricing soon. Now that I've completed the proof of concept phase anyone is free to have a machine shop of their choice do the same thing.

Here are a couple of photos of the can and rifle taken this past weekend in central Montana. I had four teenagers (sons of friends) shooting the machine gun which was really enjoyable to watch. None of them had shot a machine gun before so I was able to get through some more testing and they were able to have a good time. One of the kid's dads was present and he did a great job coaching his son and nephew through their first machine gun experience and making sure that everyone was safe. You can see from the absence of Cerakote on the outer tube where the heat is greatest. The only victim of this ~400 round shoot was the Streamlight flashlight.