New problem with a new suppressor on my AR15

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Lateck
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New problem with a new suppressor on my AR15

Post by Lateck » Tue Apr 28, 2015 10:50 pm

I have a Rock River LAR15 rifle. I have never had a single problem with it (several hundred rounds through it).
I have an AAC break on it. I have shot it with a AAC 762SDN6 with no issues (75 rounds+/-).
Today I went to the range to use my new AAC 556SD. After a few rounds I had a failure to fire. Cleared and the next round was fallowed by 2 more, by it's self. I cleared the rifle and saw no problems.... Long story short, I had 4 incidents of bump firing and 2 more ftf's. All with the can on. I did remove the can and the rifle preformed perfectly.
No pins loose or any visual problems.
Any ideas?
Thanks in advance.

Lateck,

Aaron
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Re: New problem with a new suppressor on my AR15

Post by Aaron » Tue Apr 28, 2015 11:45 pm

Almost has to be related to gas if your sure its not the ammo. I'd guess its over gassed.

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Conqueror
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Re: New problem with a new suppressor on my AR15

Post by Conqueror » Wed Apr 29, 2015 12:11 am

Need more info about your gas system, buffer, etc.
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Lateck
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Re: New problem with a new suppressor on my AR15

Post by Lateck » Wed Apr 29, 2015 1:00 am

Conqueror wrote:Need more info about your gas system, buffer, etc.
Sorry, I don't know for sure. It is a stock RR, 16". I do know it is not a piston system. (I have this one AR and I am not an expert :? )

Lateck,

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Emilio
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Re: New problem with a new suppressor on my AR15

Post by Emilio » Wed Apr 29, 2015 2:17 am

A little hard to understand your description but sounds like your bolt is cycling too fast to fully pick up the next round trying to come up from the mag. . this is because suppressors create extra blow back/gas pressure and your gas port ( hole in barrel ) may be on the big side. First thing I would do is go to a heavier buffer , you have a standard buffer then H2, then H3. I would jump straight to the H3 and see if it works both ways. You could mess with a stiffer spring also but I would try to barrow a heavy buffer to test.

Some manufactures use bigger gas ports for reliability but this is not good for cans.

You do want your gun to cycle both suppressed and non and if you slow the bolt too much weak ammo ( like Tula/ Wolf/ PMC) might not cycle unsuppressed.

Other options are changing the barrel or adjustable gas block.

now if your description was about chambered rounds not firing or doubling then never mind ,,your RRA two stage trigger has disconnector issues .
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Conqueror
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Re: New problem with a new suppressor on my AR15

Post by Conqueror » Wed Apr 29, 2015 7:52 am

Agree with above. It sounds like your rifle is over gassed. I have your buffer usually improve this. Try an H2 or H3.
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Sigproshooter
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Re: New problem with a new suppressor on my AR15

Post by Sigproshooter » Wed Apr 29, 2015 9:25 am

H2 buffer will most likely fix your timing issue.

H3 is designed for rifles that have excessive gas port erosion and a carbine length system mostly.

Adjustable gas block would be ideal, but again the H 2 will probably slow it down enough to cycle properly.
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Lateck
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Re: New problem with a new suppressor on my AR15

Post by Lateck » Wed Apr 29, 2015 10:08 am

Thank you all for your replies. :D
I'll start with the buffer as you are recommending (and the price for a buffer is reasonable). I do agree with you all on the over gassing. The ammo in the magazine started out shiny and after the bump fire, I removed the mag and the ammo looked almost like it was Russian stuff... :mrgreen:
By the way it was PMC.

Again thank you.

Lateck,

ShadesFox
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Re: New problem with a new suppressor on my AR15

Post by ShadesFox » Wed Apr 29, 2015 2:48 pm

I know my LAR15 was over gassed. It was a 16" barrel with carbine gas system. Unsupressed it ran best with an H2 buffer. I've since replaced it with a 14.5" barrel with medium gas system and that runs like a champ with and without the can.

Definitely try the H2 and maybe a H3

Lateck
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Re: New problem with a new suppressor on my AR15

Post by Lateck » Tue Jun 02, 2015 9:26 am

Follow up....
I have replaced the buffer spring with a Wolf Extra power spring and a H2 buffer. Was better, but still bumped fired, just not as often. Switched to a H3 buffer and I thought it was fixed. But on the third magazine it ran off four rounds by it's self.
I did a real good cleaning of the rifle in between swapping the H2 & H3.
I'm going to have a local smith take a look at the trigger and then I may have to order an adjustable gas block...

Your thoughts? Thanks again.

Lateck,

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Re: New problem with a new suppressor on my AR15

Post by [email protected] » Tue Jun 02, 2015 9:34 am

I'm curious if it could be a trigger issue, the hammer isn't catching when it drops back. The trigger/hammer pins aren't working loose are they?

If parts were out of spec from the factory or something was damaged, I suppose you could have an issue (and perhaps from just wear on a part that was already on the edge of failure) where the hammer is just on the edge of staying back, and occasionally slips off and returns forward.

I would put another lower on it (a buddy's or something) and see what happens.
Joshua

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Sigproshooter
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Re: New problem with a new suppressor on my AR15

Post by Sigproshooter » Mon Jun 22, 2015 7:53 am

Disconnector is bad. Probably getting ready to fail completely and not function at all.

Get rid of the s--t box G.I. trigger (good for 3,500 to 5,000 rounds) anyways and buy a geissle SSA.

Problem solved
Regard your soldiers as your children, and they will follow you into the deepest valleys; look on them as your own beloved sons, and they will stand by you even unto death.
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ShadesFox
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Re: New problem with a new suppressor on my AR15

Post by ShadesFox » Mon Jun 22, 2015 8:25 am

Most RRAs come with their 2 stage trigger. I found it really goofy and ended up replacing it. If OP has a GI trigger I would actually suggest trying that out and seeing if the bumping is because of a weak trigger.

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