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Posted: 9/5/2011 1:03:10 PM EDT
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At 100 yards, my M4-2K seems to be all over the place. I don't know if its me, the ammo, the rifle, weather, or the suppressor...
I've been trying to zero it in with the suppressor on, and I just can't seem to get any consistency at all! Didn't have the time or ammo to wait for the suppressor to cool off and try getting some repeatability even if it wasn't zeroed. I'm really worried that maybe I got a crappy can. I was shooting Winchester .55 gr 5.56. Anyone had bad results with this? |
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It is a Colt barrel. Pretty new 6940. I'm not sure what kind of washer was used cause I didn't install the 51T mount.
I checked out the baffle stack best I could using a flashlight and it looks like baffle strikes may have indeed occurred. I don't remember exactly what the stack looked like the first time I looked, but on one side of the stack they don't look perfectly round, kind of wavy. No apparent strikes on the blast baffle, last baffle, or the end-cap. I'm going to be sooo pissed. Here is a picture. Not the best, sorry. Also found this thread. Seems to be the same as I'm seeing. http://www.silencertests.com/forum/viewtopic.php?f=86&t=60440 http://i1102.photobucket.com/albums/g457/awvollmer/photo.jpg |
| I had this problem trying to sight in at 100 yds with an M4-2000, turns out my eotech was on the fritz. I put on my trijicon accupoint and got it on paper quick. It could be any weak link in the system throwing your accuracy off, in my case it was the optic. Barrel concentricity is also a common issue from what I gather, so worth checking out. Just don't want to damage that can before you rule out the things that can cause baffle strikes. Good luck! |
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Yeah, about the washer, I trust the guy that installed the brake. Accuracy is pretty good. I've shot it a lot more at 50 than 100 but the current optic (trijicon 4x) is sighted in @ 100. My problem is I'm not getting repeatable POI. I'm thinking it's me, the weather (wind, heat, etc), or the ammo. The rifle has been GTG for accuracy un-suppressed as far as I'm concerned. As I said though, I didn't have the ammo/time/money to zero it in un-suppressed and suppressed today. :-/
Also, let me say this; I haven't been shooting seriously for very long, so there's probably a lot of things I'm doing wrong with my basic zeroing set up. I have a bipod, but I don't really use sandbags. I know how to mechanically zero BUIS or optics, but the general set up needed is a little fuzzy to me. |
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Is there a little side to side (rotational) wobble when you tighten up the suppressor? Like its not fully tight on the mount?
Mine was similar to what you describe until a little carbon got everything tightened up. Now there is zero movement between the can and the mount and the group sizes don't change with/without suppressor. 
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Quoted:
It is a Colt barrel. Pretty new 6940. I'm not sure what kind of washer was used cause I didn't install the 51T mount. I checked out the baffle stack best I could using a flashlight and it looks like baffle strikes may have indeed occurred. I don't remember exactly what the stack looked like the first time I looked, but on one side of the stack they don't look perfectly round, kind of wavy. No apparent strikes on the blast baffle, last baffle, or the end-cap. I'm going to be sooo pissed. Here is a picture. Not the best, sorry. Also found this thread. Seems to be the same as I'm seeing. http://www.silencertests.com/forum/viewtopic.php?f=86&t=60440 http://i1102.photobucket.com/albums/g457/awvollmer/photo.jpg That is normal. |
| It seems to be a common thing with the M4-2000. Sometimes it clears up, sometimes not. It's due to the tolerances between the mount and can not always stacking up well enough to mount the can tightly. The only real solution seams to be to keep tryin different mounts until you find one that fits tight. |
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There is some shift to the left and right when I tighten it on. It is that feeling like the ratchet goes past the last tooth, doesnt quite get over the next and is loose from the distance between almost over the next tooth and the last tooth it actually did go over. Does that make sense?
Ill add some more pics soon. Thanks for all the input so far. |
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There is some shift to the left and right when I tighten it on. It is that feeling like the ratchet goes past the last tooth, doesnt quite get over the next and is loose from the distance between almost over the next tooth and the last tooth it actually did go over. Does that make sense? Ill add some more pics soon. Thanks for all the input so far. Sounds exactly like my friend's problem... he was afraid to really honk it on there. But eventually he did and it fixed his problem. Now, that lead to another problem... the can was tough get off after 200 or so rounds. I 'd see if you can tighten it one more click. That mount system is the only thing I'm not crazy about on AAC cans. |
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What a novel idea! I haven't actually called them. That is first on my list to do tomorrow when people aren't bothering me at work. BTW here is another picture of the baffle stack. Again not the best picture, but I don't know how to get any better: http://i1102.photobucket.com/albums/g457/awvollmer/photo-1.jpg Not a strike. Scared the crap out of me when I saw this on my M4-2000, but it's the way the baffles are designed. They are cut different on one side than the other. |
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There is some shift to the left and right when I tighten it on. It is that feeling like the ratchet goes past the last tooth, doesnt quite get over the next and is loose from the distance between almost over the next tooth and the last tooth it actually did go over. Does that make sense? Ill add some more pics soon. Thanks for all the input so far. Sounds exactly like my friend's problem... he was afraid to really honk it on there. But eventually he did and it fixed his problem. Now, that lead to another problem... the can was tough get off after 200 or so rounds. I 'd see if you can tighten it one more click. That mount system is the only thing I'm not crazy about on AAC cans. BTW, I just wanted you to know, that the "really honk it on there" comment has be chuckling every time I read it. Also, just how hard did he have to "honk" it on? I twisted it pretty good and it's not getting over that last tooth. Did he use tools? |
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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. |
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Quoted:
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. Let us know if that fixes your issue. I have an M42K and haven't had any issues with it but this is good to know should any issues arise. |
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There is some shift to the left and right when I tighten it on. It is that feeling like the ratchet goes past the last tooth, doesnt quite get over the next and is loose from the distance between almost over the next tooth and the last tooth it actually did go over. Does that make sense? Ill add some more pics soon. Thanks for all the input so far. Sounds exactly like my friend's problem... he was afraid to really honk it on there. But eventually he did and it fixed his problem. Now, that lead to another problem... the can was tough get off after 200 or so rounds. I 'd see if you can tighten it one more click. That mount system is the only thing I'm not crazy about on AAC cans. BTW, I just wanted you to know, that the "really honk it on there" comment has be chuckling every time I read it. Also, just how hard did he have to "honk" it on? I twisted it pretty good and it's not getting over that last tooth. Did he use tools? He didn't have to use tools, but he did have to two hand it on. After doing it a couple times, it secures easier now. Does it twist at all when it won't click? And you say when tightened as much as you can, it still has a bit of play? Definitely some kind of mount issue, I'm thinking.... |
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Quoted:
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. Let us know what your experience is. Hopefully Mr Hollister there identified your problem. Doesn;t sound exactly like what you were describing, but give it a shot, so to speak. :) |
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I think that sounds exactly like what I'm experiencing. So my question now is: is there SUPPOSED to be a little play back and forth? Sounds like that's what Mr. Hollister is suggesting. Yes, there is. Is your problem that your groups are opening up while shooting or are the poa /poi changing between having the can off and on? If it's during firing,make sure the can is in the valley,which will also leave play. If it's the latter,then have witness marks for the two zeroes you'll now be switching back and forth from. |
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UPDATE
First what do you mean by witness marks from the two zeros? Took my can to the range today and followed Mr. Hollister's advice. Overall, my groups were FAR tighter, much more in line with what I was getting with the can off. I'm pretty sure that the grouping is mostly limited by my physical shooting ability. I'm not exactly shooting sub MOA, the groups are a few inches ( <2 ) with a 4x Trijicon @ 100 yards. How's this sound to you guys? |
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I think that sounds exactly like what I'm experiencing. So my question now is: is there SUPPOSED to be a little play back and forth? Sounds like that's what Mr. Hollister is suggesting. That sucks, on my bolt gun if the can is loose it kills my groups, they go from sub-1" to about 2". 
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I think that sounds exactly like what I'm experiencing. So my question now is: is there SUPPOSED to be a little play back and forth? Sounds like that's what Mr. Hollister is suggesting. MY M4-2K is the 18 tooth, so this may not apply, but I get the tightest groups by tightening the threads down - not by letting the retention mechanism rest between teeth (where some play exists) . |
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UPDATE First what do you mean by witness marks from the two zeros? Took my can to the range today and followed Mr. Hollister's advice. Overall, my groups were FAR tighter, much more in line with what I was getting with the can off. I'm pretty sure that the grouping is mostly limited by my physical shooting ability. I'm not exactly shooting sub MOA, the groups are a few inches ( <2 ) with a 4x Trijicon @ 100 yards. How's this sound to you guys? I'd say the groups are actually limited by your sight choice. Betcha get MoA groups with a crosshairs type sight with 9x magnification. |
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Quoted:
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. They actually shoot really nice when the spring rests between two teeth with the mount in tension. I participated in the SCAR T&E program for a military unit and the can / 10.5" SCAR lite I was issued for that had a mount that fit perfectly, with the spring between two teeth when the mount was totally tight. The shift was really small (less than 1MOA) <granted this was the old flat baffle and two cones settup, the groups were good. It works better as a tension mount. Perhaps they should make a change to make that happen. You can take them to a reputable machine shop to have the angled surface of the mount ground until it does fit properly in tension if you're having accuracy issues. It just increases the cost acquiring a good mount. |
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