AAC 51T Mount? Are they good?

[Falcon03]

I have a 762SD 51T mount that I have only shot once so far. I did have some backlash because I could not reach the next tooth.
I turned it as tight as I could get it by hand. At the end of the day I went to remove the can and found that it did not back off, it was in the same tight position as when I started shooting. It seems that the carbon from shooting locked it in place.
I have never read about this before but in my case it does not seem to be a problem. My shot groups were tighter with the can on which seems to be the norm with cans.

[66427vette]

aac mounts are nice but it is no red jacket.

[JasonM]

I have seen posts about people having 51T mounts that don't snug up, etc. and have even heard of POI shift being inconsistent due to this. I have also read of the ratchet on the silencer wearing out.

Is the AAC mounting system a good one, or is it possible or even likely that only 1 or 2 positions on my MITER system will lock up tight? Are people who are having issues just being weenies and not cranking down on the can a bit to get it to the next tooth?

I've already bought my AAC, just waiting on it to get here, and am having a bit of mental anguish over the volume of posts on this and other sites about the ratchet mounting method.

The 51T mount is very good. You tighten the can as far as possible, then back it off to the next closest tooth and go to town. consistent POI shift, easy removal. The ratchet latch wear is a non-issue, it'll wear, but very very rarely wear out. If it ever did, AAC will replace it.

what you describe is possible on the Miter system, but should not affect function. It will certainly affect sitting-on-your-couch-over-thinking, but not function on the range.

People had problems with the 18T mounts backing off sometimes, and they do. The 51T's don't back off and are very solid. You are over thinking it and you'll be fine.

[bigdog2003_99]

^^ +1000

my m4-2k is on and off of my rifles alot and there is no sign of any wear whatsoever, i also do the tighten it fully and rotate it back so it seats between the teeth properly to get a consistant poi every time

[copenhagen]

The 51T mount is so horrible that I own 5 of them.

[66427vette]

I'm just worried about longitudinal play causing bafflestrkes. Is the play axial only, or longitudinal as well?

I would be more worried about ATF taking their sweet time with your approval. Never had an issue with any aac can or product and I own a bunch.

[JasonM]

I'm just worried about longitudinal play causing bafflestrkes. Is the play axial only, or longitudinal as well?

You are over thinking it. tolerances are built into the system. Thousands and thousands and thousands are out there. They work.

The cans have a tapered EDM'd bore to compensate for any play and for most bullet instability.

[Ryo]

I've only seen one baffle strike on a AAC can (M4-2k) so far, and that was user error. AAC/Mike took care of him even though it was user error (actually friend user error of not screwing it down) and didn't charge him a dime.

[JasonM]

How does that work? What kind of tolerance is there?

Fingering this thing with my mind and keyboard because...it's not here

The bore is larger than the bullet. the bore is also a very slight cone- larger at the muzzle end. You'll be fine.

[JasonM]

How does that work? What kind of tolerance is there?

Fingering this thing with my mind and keyboard because...it's not here

The bore is larger than the bullet. the bore is also a very slight cone- larger at the muzzle end. You'll be fine.

Is accuracy not effected by the can being loose (ie. tighten down, then back off 1 tooth so the latch is in the valley between the teeth?)

Some people say this kills their grouping.

Not in my experience. This movement if present at all is very small and goes away completely once a little carbon gets introduced to the system.

Groups should be tighter than without the can.

[Old Wanderer]

1st I would like to nominate myself for the Dumb. Sh....t award of the year.

Yesterday I took my 2 new cans to the range. I have a new 762SD and a M4-2000. I was shooting a Rem 700 308, and a M4 carbine.

I had a friend with me from the local army base. He wanted to go shooting with me for a while, and is deploying for Afghanistan in a few months. He asked about trying the 308 with a can to see what it was like. Sure I said, and reached in my bag and grabbed a can and screwed it on the Remington, and handed it to him...After a few shots, he said it was not even hitting the 200 yard target...(this is a under .5 MOA rifle). I fired one shot, looked, then fired a second shot at the 50 yard target...There he told me I hit the berm 20 yards in front of the target. I sat the gun over on the next table, in disgust, and decided I would see what was wrong with my high dollar scope when I got home. 20 min later, I went to put the can on my M4, when I realized I had screwed the M4-2000 on the 308. (@#@#$%%%$#@!!@###), I took it off and a bunch of "stuff" fell out. I was sick....I had fired less than 10 rounds through this can since new.

Later in the day, I decided to screw it on my M4, just out of curiosity. It worked fine. Yes there is a bit of a bulge on the exit of the can where the bullet struck it, so I'm sure accuracy will suffer some, but I have to say....AA cans are tough.

We fired 7 rounds of 308 through a 556 can, and it kept working fine when it finally got installed on the right gun. I fired about 50 rounds through it after the damage.

So anyone that thinks a tiny bit of "wiggle" will destroy your silencer, I have some ugly proof, that your worries are just theoretical fantasies.

[Jon L]

1st I would like to nominate myself for the Dumb. Sh....t award of the year.

Yesterday I took my 2 new cans to the range. I have a new 762SD and a M4-2000. I was shooting a Rem 700 308, and a M4 carbine.

I had a friend with me from the local army base. He wanted to go shooting with me for a while, and is deploying for Afghanistan in a few months. He asked about trying the 308 with a can to see what it was like. Sure I said, and reached in my bag and grabbed a can and screwed it on the Remington, and handed it to him...After a few shots, he said it was not even hitting the 200 yard target...(this is a under .5 MOA rifle). I fired one shot, looked, then fired a second shot at the 50 yard target...There he told me I hit the berm 20 yards in front of the target. I sat the gun over on the next table, in disgust, and decided I would see what was wrong with my high dollar scope when I got home. 20 min later, I went to put the can on my M4, when I realized I had screwed the M4-2000 on the 308. (@#@#$%%%$#@!!@###), I took it off and a bunch of "stuff" fell out. I was sick....I had fired less than 10 rounds through this can since new.

Later in the day, I decided to screw it on my M4, just out of curiosity. It worked fine. Yes there is a bit of a bulge on the exit of the can where the bullet struck it, so I'm sure accuracy will suffer some, but I have to say....AA cans are tough.

We fired 7 rounds of 308 through a 556 can, and it kept working fine when it finally got installed on the right gun. I fired about 50 rounds through it after the damage.

So anyone that thinks a tiny bit of "wiggle" will destroy your silencer, I have some ugly proof, that your worries are just theoretical fantasies.

Get in touch with AAC. It may cost you, but I bet they can repair your M42k.

[Ryo]

My friend had his M42k baffle strike fixed as well. Sorry to hear you damaged yours. Definitely they can fix it to make it look new. Contact Mike Mers to see what they can do. With my friend it was fixed for free, but someone who is more in the industry asked for favors to get it fixed.. and so he fixed it for free. You never know you might get your fixed for free...

[DEVIL DOC]

I have used super fine sand paper like 1500 grit an cleaned the threads to a polish and my can locks all the way to a tight last click. Hoppes elite will melt the carbon right off the mount.

[Old Wanderer]

Well I fixed it myself.

There were no problems with the threads, and it locked up tight on my M4.

I called AA and they told me they were designed for this kind of abuse and as long as there was no bulging in the tube and the end cap was OK, it was good to go.

So I took my suppressor, sat it on my mill table, took a 2# mallet, and gently tapped the end cap back to flush. (It had a .030 area on one side of the exit hole, where a bullet had stuck it). The exit hole is concentric, and other than seeing some erosion on the 1st baffle entrance, you would never know some idiot had put this on the wrong gun.

My compliments and admiration to AA for a really tough product.

[Ryo]

Well I fixed it myself.

There were no problems with the threads, and it locked up tight on my M4.

I called AA and they told me they were designed for this kind of abuse and as long as there was no bulging in the tube and the end cap was OK, it was good to go.

So I took my suppressor, sat it on my mill table, took a 2# mallet, and gently tapped the end cap back to flush. (It had a .030 area on one side of the exit hole, where a bullet had stuck it). The exit hole is concentric, and other than seeing some erosion on the 1st baffle entrance, you would never know some idiot had put this on the wrong gun.

My compliments and admiration to AA for a really tough product.

No photos of the accident?

[JasonM]

I called AA and they told me they were designed for this kind of abuse and as long as there was no bulging in the tube and the end cap was OK, it was good to go.

A 5.56 can was designed to have 308 shot through it? I'm sure it held together, but there must be a good amount of damage...

[DEVIL DOC]

I called AA and they told me they were designed for this kind of abuse and as long as there was no bulging in the tube and the end cap was OK, it was good to go.

A 5.56 can was designed to have 308 shot through it? I'm sure it held together, but there must be a good amount of damage...

I dont know how my M4-2k would sound after a few 7.62s through it. I bet it would be fucked.

[Old Wanderer]

I called AA and they told me they were designed for this kind of abuse and as long as there was no bulging in the tube and the end cap was OK, it was good to go.

A 5.56 can was designed to have 308 shot through it? I'm sure it held together, but there must be a good amount of damage...

I dont know how my M4-2k would sound after a few 7.62s through it. I bet it would be fucked.

Well that is why I put my M4-2000 on my M4 after being stupid. To me and my "friend", there was no difference in the sound of the suppressor on the M4 after the incident. The 1st baffle shows some ugly erosion, where it stripped the copper jacket off the bullet, and may result in some shorter life. However the exit hole is still well below a 30 cal diameter.

Let me clarify, what AA said. When I described what I had done, they indicated that during development they anticipated this kind of error. Had tested it so the can would not be destroyed. The last shot I fired, hit a berm 20 yards in front of my 50 yard target. So while I did fire 7 rounds of 308, all that came out the other end was the lead core, and zero for accuracy. Another factor is I was shooting 168 Gr Sierra Match Kings, so they have a thin jacket

They indicated if I had no bulging in the body, and the end cap was OK, just go ahead and shoot it. (With the correct caliber!!!!!!!!!!!!)

[DEVIL DOC]

By "they" I'm assuming the little green men in your shooting party?

[JohnnyC]

Where did Goes2Eleven's posts go? He was asking good questions and Jason was providing good answers.

[JasonM]

Where did Goes2Eleven's posts go? He was asking good questions and Jason was providing good answers.

he emailed me that his account got deleted... weird.

I thought he was doing fine. ?

[Unobtanium]

Guy on ar15.com wore his latch out in just a few months (Feb.2011 he got his m4-2k). Did a few get out without the correct heat treatment?



Has anyone noticed group size being affected by a rock solid lock up vs. the "correct" method of tighten, then back off a tooth? It sounds like if aac designed the can to be loose, and the latch as a retention vs. tensioning system, then this is the correct way, and people are just misunderstanding the manual of arms for the product. However, its always in the back of the mind that this is a band-aid type instruction to correct for the mounting system not being 100% as intended. I think that is what some people are concerned over.

[billybronco]

i was under the impression that the "back off a tooth" recommendation was designed to aid in removal in the inevitable event that carbon made it's way into the system.

?

[Unobtanium]

i was under the impression that the "back off a tooth" recommendation was designed to aid in removal in the inevitable event that carbon made it's way into the system.

?

From John Hollister at AAC

Typically where there seems to be an issue is not the silencer in a valley between the two last teeth, it is shooters typing to muscle the silencer over the very last tooth to try and tension the silencer. The 51T mount is not a tensioning system, it is a retention system.

When you muscle the silencer and get it to "stick" you are actually just catching the latch on the 45degree face of the next tooth. When the first round is fired the latch drops back into the valley and subsequent shots group nicely. Again, typically shooters see a group and one flier, the flyer being the first shot fired.

The solution is to wind the silencer all the way on and pull back one to drop it into the valley and you should see your groups get better without a flier.