Issue with a brand new AAC M4-2000

[Titleist]

My form 4 came back yesterday, so I picked up the M4 2000 mod. 08 from my FFL/SOT.

It's just plain awesome. That said after 30 rounds, using Federal XM193 on my brand new LMT 10.5" SBR (blackout was installed correctly), I noticed a tiny bulge muzzle rim of the can.

Nothing major, but it concerns me. The suppressor was cranked down the whole way, nothing improper took place, and I've checked the barrel to make sure nothing odd is going on. We also checked the targets and it's not keyholing, nor baffle strikes.

But I'm hesitant to keep shooting the gun if I'm going to make it worse.

Is my best bet to have it sent back to AAC?

[Derek_Connor]

My form 4 came back yesterday, so I picked up the M4 2000 mod. 08 from my FFL/SOT.

It's just plain awesome. That said after 30 rounds, using Federal XM193 on my brand new LMT 10.5" SBR (blackout was installed correctly), I noticed a tiny bulge muzzle rim of the can.

Nothing major, but it concerns me. The suppressor was cranked down the whole way, nothing improper took place, and I've checked the barrel to make sure nothing odd is going on. We also checked the targets and it's not keyholing, nor baffle strikes.

But I'm hesitant to keep shooting the gun if I'm going to make it worse.

Is my best bet to have it sent back to AAC?


On the timeline of a suppressor, you are eventually going to get a bullet go a bit sideways. Usually its after heavy sustained volumes of fire when everything is hot, and drooping a bit.

Unfortunately, it seems like this incident arrived real early in your can's lifetime.

If its not key holing, I'd just enjoy the can. Keep shooting it, it will be fine.

FWIW, I still run a M4/SPR thats been to hell and back, decent sized end cap strike, no key holes, still accurate, still works, and its past 10k rounds.

[RetreatHell]

I don't really have anything to say that could help you figure anything out, but I'm just curious to know exactly what "key-holing" is??

I just got my first suppressor the other day, and "key-holing" is the only term I have never heard of before.

Like I said, just curious. If anyone could chime in and explain it, that would be great.

Thanks in advance!

-Paul

[chrismartin]

I don't really have anything to say that could help you figure anything out, but I'm just curious to know exactly what "key-holing" is??

I just got my first suppressor the other day, and "key-holing" is the only term I have never heard of before.

Like I said, just curious. If anyone could chime in and explain it, that would be great.

Thanks in advance!

-Paul

http://home.comcast.net/~sfischer397/temp/keyholes.jpg

Basically, the bullet is very unstable when it exits the barrel that it wobbles so bad, it turned sideways. If you shoot paper, it will look like the profile of the bullet, similar to a keyhole in a lock.

There can be various degrees of instability and any of it can cause a baffle or end cap strike. Just think, the aperture at the end of the silencer is a little bit bigger than the bullet itself, so ANY wobble in the bullet can hit the edge. Some hits will just nick, nothing but surface damage, some take out all the guts of the silencer and destroy it.

ETA: Even a normal shooting gun can have a weird round that causes an end cap strike. Even user error can cause a strike (like not making sure the silencer is tight) I have a little strike on the end of my Pilot .22lr silencer. It wasn't caused by any of my guns as the shoot great and the threads are perfect. It was most likely user error or a strange round that nicked it.

[Titleist]

Before I talked with Derek about his experiences with suppressed SBRs I emailed AAC concerning my end cap strike. Regardless of if they say "run it and in 10K rounds give us a call" that's fine, I just want to talk with them to make sure I'm not going to aggravate it if something is in fact wrong. Then at least I can know I did due diligence.

Anyways, out of the 30 rounds I fired they were all holes, no keyholes in the bunch. And my suppressor was locked down all the way.

[markm]

Don't shoot that ****ing TRASH XM193 thru your can.

I've found 3 rounds recently where the BULLET is "bent" for lack of a better term. The bullet is tweaked to one side and the case neck is bent too.

All of these check out when run in my case guage, but are obviously ****ed up just by looking at them... yet if you were loading a mag quickly, you might not catch it. If you roll the round on the table, you can watch the bullet tip wobble. If you didn't shoot these turds through a silencer, you'd just think you pulled your shot.

I'm now convinced that this is what cause the baffle strike in my AAC can because I can narrow my incident down to a 25 round window.

If you continue to use this craptastic ammo, hand check EVERY SINGLE ROUND that you plan to run through your can because there's a lot of shit in those 20 round boxes. :mad:

[Derek_Connor]

Mark has a point.

We all have seen reduced quality ammo being put out lately, even the factory stuff.

[Iraqgunz]

Mark,

Have you had a chance to run any of that M855 yet? I contacted Lake City/ ATK and they said it is good to go stuff.


Don't shoot that ****ing TRASH XM193 thru your can.

I've found 3 rounds recently where the BULLET is "bent" for lack of a better term. The bullet is tweaked to one side and the case neck is bent too.

All of these check out when run in my case guage, but are obviously ****ed up just by looking at them... yet if you were loading a mag quickly, you might not catch it. If you roll the round on the table, you can watch the bullet tip wobble. If you didn't shoot these turds through a silencer, you'd just think you pulled your shot.

I'm now convinced that this is what cause the baffle strike in my AAC can because I can narrow my incident down to a 25 round window.

If you continue to use this craptastic ammo, hand check EVERY SINGLE ROUND that you plan to run through your can because there's a lot of shit in those 20 round boxes. :mad:

[SHIVAN]

I emailed AAC concerning my end cap strike. Regardless of if they say "run it and in 10K rounds give us a call" that's fine, I just want to talk with them to make sure I'm not going to aggravate it if something is in fact wrong. Then at least I can know I did due diligence.

One of our main rules is to do just what you've done, and let them respond, before posting about an "issue" that might or might not be anything to worry about.

The internet has a long memory, and someone may quote your "issue" later making a bad name for AAC -- or other vendors.

When you hear back from them, let a mod or staff member know and we'll unlock this thread for an update.

Thanks.

[SHIVAN]

It would appear that AAC has had a chance to look at this suppressor, and there has been a definitive resolution. I'll let the OP respond now.

Thanks all for your patience while we afforded AAC a chance to respond.

[Titleist]

Thanks Shivan. I wanted to give a quick update on this. First off I want to express my gratitude to AAC, especially Mike Mers @ AAC.

Mike took the LMT upper apart, and inspected the barrel, flashhider, threads, etc.

The response was that the flashhider was on absolutely straight (much to my relief, as I was worried I had borked that process up even though I followed instruction to the letter). Threads were spot on, barrel, etc. The overwhelming theory lines up with what has been said before, that a round may have been poorly seated in the casing, or a weak primer may have caused an under-powered round.

Either way, no baffle strikes, and just a small nick, resulting in a small bulge on the end cap. So this was not a fault of the AAC product, and in Mike's words, "just bad luck". I want to go on record thanking them for still offering to replace the end cap and make it look good as new.

Thanks again to AAC, and I appreciate all the advice I got here on this thread.

[SWATcop556]

Glad to hear that AAC made it right and worked with you. Did you take them up on the endcap replacement?

I was also wondering if you have photos of the strike?

[C45P312]

Thanks for the update

[Titleist]

I find dealing with product issues to show a LOT about a company. KAC, and AAC, are now at the top of my customer service "cool guys" list.

At first I figured the conversation with Mike would end with, "so we're just gonna send it back" i.e without the end cap being addressed. "So we'll replace the cap obviously."

So it wasn't even a question. Plus they offered to paint it tan if I wanted, I opted for black. ;)

Anyways, some images of the small strike. Again let me stress before everyone says (my god that's tiny why did you freak out), that I sent the upper and M4-2K in as a preventative measure. In that I didn't want this to be the start of a bigger issue, so I sent it back to the manufacturer to have their expert opinion before I potentially did anymore damage Anyways, pictures:

http://lawndartdesign.com/guns/AAC_issue_01.jpg
http://lawndartdesign.com/guns/AAC_issue_02.jpg

Thanks again for all the advice.

[C4IGrant]

Don't shoot that ****ing TRASH XM193 thru your can.

I've found 3 rounds recently where the BULLET is "bent" for lack of a better term. The bullet is tweaked to one side and the case neck is bent too.

All of these check out when run in my case guage, but are obviously ****ed up just by looking at them... yet if you were loading a mag quickly, you might not catch it. If you roll the round on the table, you can watch the bullet tip wobble. If you didn't shoot these turds through a silencer, you'd just think you pulled your shot.

I'm now convinced that this is what cause the baffle strike in my AAC can because I can narrow my incident down to a 25 round window.

If you continue to use this craptastic ammo, hand check EVERY SINGLE ROUND that you plan to run through your can because there's a lot of shit in those 20 round boxes. :mad:


Mark is correct. Federal XM193 is INFAMOUS for putting out some of the worst ammo around. Remember that the "X" basically stands for REJECTED AMMUNITION!


C4

[markm]

Anyways, some images of the small strike. Again let me stress before everyone says (my god that's tiny why did you freak out), that I sent the upper and M4-2K in as a preventative measure. In that I didn't want this to be the start of a bigger issue, so I sent it back to the manufacturer to have their expert opinion before I potentially did anymore damage

Not at all. Any hint of baffle/cap strike is reason for alarm.

I pretty much only shoot my handloads through my silencer. I definitely am cautious about any XM193 I run through it.

[Derek_Connor]

misfire.

[Titleist]

I've shot suppressed before, but never my own gun, and this marks my first 'can' so I wanted to nip any potential issues early.

If XM193 is decent enough to run un-suppressed, what would be the best ammo (without breaking the bank) for running suppressed? Not subsonic, but more or less quality control.

[decodeddiesel]

Mark has a point.

We all have seen reduced quality ammo being put out lately, even the factory stuff.

From Federal? Never...:rolleyes:

http://i19.photobucket.com/albums/b200/decodeddiesel/FCSMKFail008.jpg

[markm]

I've shot suppressed before, but never my own gun, and this marks my first 'can' so I wanted to nip any potential issues early.

If XM193 is decent enough to run un-suppressed, what would be the best ammo (without breaking the bank) for running suppressed? Not subsonic, but more or less quality control.

I'd shoot much of the .223 that's out there. The walmart Fed bulk pack is really not bad. Prvi M-193 seems to be decent. If you can get that PMC bronze you might try some of that. I've shot the PMC in my can with good luck.

I'd treat UMC almost like XM193. Look it over carefully before shooting it.

[Titleist]

I'll give some some M193 and PMC a try. I'll just snag some of that and set aside for when I run suppressed. Taking a Magpul Dynamics course in late july, but wasn't planning on shooting suppressed that much outside of later in the day/evening. Thanks again, all this advice is invaluable.