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Suppressors AAC 18T cheap fix

frankythefly

Sergeant
Full Member
Minuteman
Aug 30, 2010
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For those that have an ACC 7.62SD or something else that takes the 18T adapter I have a mod that will keep your can from rotating and also a way to adjust POI.

This has been tested at least 500 rounds for me from .300 Blackout to .308 win no issues at all. Also my friend just did this to his can and he has no issues either.

All I did was go to the hardware store pick up these items:
allen screw,
appropriate tap,
drill bit.

Next remove one of the springs inside the can, and use the spring retaining hole as a pilot hole for your drill bit.
Drill the hole, then tap it.

Easy as that.

Anyhow I can make detailed instructions for those who want them and send out the bit, tap, and allen screw(s) to you. I made mine so that when I screw it all the way down the top of the screw is flush with the can.

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Re: AAC 18T cheap fix

The length on the one I used is .25inches, width is ~.15 inches

also note that the screws I found taper down to somewhat of a point which makes it a prefect fit between the teeth of the adapter.
 
Re: AAC 18T cheap fix

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: frankythefly</div><div class="ubbcode-body">The length on the one I used is .25inches, width is ~.15 inches

also note that the screws I found taper down to somewhat of a point which makes it a prefect fit between the teeth of the adapter. </div></div>

Put some marking paint on the end of the screw and tighten it down on the brake. When you take it off the paint should leave you a circle. Hit that with a big punch and that will give you an indexing point that the set screw can really lock into.
 
Re: AAC 18T cheap fix

I was thinking about doing that, however with minimal torque applied to the screw I have not had any issues. I shot about 100rds of .308 today and another 100 rapid fire from a 5.56 gasser and had no rotation or POI shift. Even when un/re installing the can the zero was maintained.

PM me if anyone wants me to send them the bit, tap, and screws I used. I only use high grade US-made taps and bits so plenty of life yet on them.
 
Re: AAC 18T cheap fix

I'm somewhat curious...How are you adjusting POI shift (and maintaining a good lockup on the somewhat corse screw thread)? I am interested.

Thanks!
 
Re: AAC 18T cheap fix

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: frankythefly</div><div class="ubbcode-body">I was thinking about doing that, however with minimal torque applied to the screw I have not had any issues. I shot about 100rds of .308 today and another 100 rapid fire from a 5.56 gasser and had no rotation or POI shift. Even when un/re installing the can the zero was maintained.

PM me if anyone wants me to send them the bit, tap, and screws I used. I only use high grade US-made taps and bits so plenty of life yet on them. </div></div>

Don't suppose you have links or anything to the exact stuff you used?
 
Re: AAC 18T cheap fix

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Poison123</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: frankythefly</div><div class="ubbcode-body">I was thinking about doing that, however with minimal torque applied to the screw I have not had any issues. I shot about 100rds of .308 today and another 100 rapid fire from a 5.56 gasser and had no rotation or POI shift. Even when un/re installing the can the zero was maintained.

PM me if anyone wants me to send them the bit, tap, and screws I used. I only use high grade US-made taps and bits so plenty of life yet on them. </div></div>

Don't suppose you have links or anything to the exact stuff you used? </div></div>

He told you the pitch of the screw he used. You can determine from that the correct drill bit and tap. Drill it out.... turn the tap slowly with some oil on it and you are good to go.
 
Re: AAC 18T cheap fix

I can just mail everything that you will need, and you can just mail it to the next guy who needs the stuff. I have no use for it.
 
Re: AAC 18T cheap fix

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mjb2</div><div class="ubbcode-body">I'm somewhat curious...How are you adjusting POI shift (and maintaining a good lockup on the somewhat corse screw thread)? I am interested.

Thanks! </div></div>
All I did was tighten the can all the way down and back off a tooth or two and then screw the allen in. (depending on the rifle it would lessen the zero shift distance) My old zero shift on my ar-15 was about 1-2 MOA depending now it is half that. It is not a fine adjustment but better than nothing.
 
Re: AAC 18T cheap fix

Have you tried this on the 51 tooth QD ? And can the spring be replaced if need be or does the drilling of the whole precled that ?

Looks like a very good idea .
 
Re: AAC 18T cheap fix

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hogrider</div><div class="ubbcode-body">Have you tried this on the 51 tooth QD ? And can the spring be replaced if need be or does the drilling of the whole precled that ?

Looks like a very good idea . </div></div>

I'd assume you'd need a much smaller screw for the 51T stuff.
 
Re: AAC 18T cheap fix

I agree but I cannot tell if the screw has a fairly sharp point or if it is just rounded. I have two AAC 7.62 SD. The first came with the 18 tooth and the second about 18 months later came with the 51 tooth QD.

Both suppressors will back off after 20/30 rounds if I do not pay attention to them. That screw should solve that problem as well.
 
Re: AAC 18T cheap fix

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hogrider</div><div class="ubbcode-body">I agree but I cannot tell if the screw has a fairly sharp point or if it is just rounded. I have two AAC 7.62 SD. The first came with the 18 tooth and the second about 18 months later came with the 51 tooth QD.

Both suppressors will back off after 20/30 rounds if I do not pay attention to them. That screw should solve that problem as well. </div></div>

The screw is just rounded, if you truly wanted to you could take a longer screw and grind the bottom to a point to the exact shape of the gap between the teeth.

The 7.62sd has 2 springs you only need to remove the one closer to the qd opening.

From an engineering stand point it would of been easier to make a better latching system with less teeth not more. For military field stuff I believe the K.I.S.S. way of doing things is the way to go. I have a design that utilizes a better latching system using a detent and titanium spring (Not a Cheap fix) for the 18T adapter. However a 51T, 90T, 3000T, etc.. would make it even more complicated.

I will be sending off the kit to the first guy with an assortment of different screw lengths that you can all mess with and try out.
 
Re: AAC 18T cheap fix

Currently in Afghanistan. When I return I will get in touch and talk to you about this. I would like a fix for both the 18 and 51 tooth. Love the suppressors and all but the QD could use a lot of improvement.

Thx
 
Re: AAC 18T cheap fix

Fantastic, would love to see a 51t implementation.
 
I ended up sending it back to aac for repair. After they told me they would not repair anything on the can under warranty or even for a repair cost if a set screw or any other mods have be preformed. So I m forced to wait 3 weeks or gamble hope it last for ever!
 
I was getting new C springs put in about every year. It was a small inconvenience. But it's a good can suppression wise.

Deano
 
Would sure be nice if you could service yourself... From what they telle it pretty in-depth.