Problem with my M16 - Page 1

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Posted: 8/21/2016 8:33:54 PM EDT

I have a couple of M16's, one of which is shot on a regular basis, it currently has around 6k rounds on it with a very high percentage of those done on full auto.

Here's the spec's-

M16 lower
Geissele SSF trigger
Carbine buffer tube/Sopmod stock
Spikes T2 buffer
Original seer

Upper-
10.5" LMT upper built by High Caliber Sales
AAC M4-2000

Here's my issue-

The gun has functioned flawlessly for years. The past few months it has started acting up who fired in full auto. Shooting the gun in bursts is not a problem but doing a mag dump is.

The guns failure is a partial failure to eject, the gun stove pipes but hasn't tried to load the next round.

What I have checked/changed to date-

I replaced the gas rings
I have replaced the buffer spring

I am at a loss now as to what the problem can be. It seems to me that the BCG velocity is off(sorry if this isn't the right terminology). I say this becasue if I remove the suppressor the gun functions great, I noticed to today if I really oil the bolt carrier that it was good for a few mags before it started acting up again.

Anyone have any ideas as to what I might look at next?

I disassembled the gun today and can't find any issues with the tube. I wanted to check the barrels gas port and the front sight base port but the front sight isn't coming off with out destroying it.

Thanks in advance for any help.

Posted: 8/21/2016 8:36:36 PM EDT

[#1]

Might try putting a new ejector spring in it.

Posted: 8/21/2016 8:44:11 PM EDT

[#2]

I agree,

It sounds as if your ejector is not working correctly, it is probably worn out, I keep a couple on hand all the time for my 16's

I have had to change a few of them over the years.

Posted: 8/21/2016 8:54:35 PM EDT

[#3]

I haven't ever considered it being an ejector issue. I have a few spare bolts, I will try that next.

Posted: 8/21/2016 10:20:41 PM EDT

[#4]

I would try and narrow it down by swapping parts and see the results. Try a spare BCG and see if that helps. If you still have issues even with a diff BCG then it might be an issue with your gas system.

Fwiw I had issues with mine not locking back on the last shot. Went to replace the bolt catch and found it caked with gunpowder. Decided to strip the whole lower and clean it up. At some point firearms just need some heavy maintenance.

Posted: 8/21/2016 10:45:54 PM EDT

[#5]

Could be a worn end on the gas tube caused by mis-alignment at installation.

Sounds like a short stroke and not an ejector issue.

If it was the ejector, it should at least attempt to pick up the next round.

Posted: 8/22/2016 8:00:50 AM EDT

[#6]

Quote History

Quoted:
Could be a worn end on the gas tube caused by mis-alignment at installation.

Sounds like a short stroke and not an ejector issue.

If it was the ejector, it should at least attempt to pick up the next round.

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Agreed. It seems like it's not going back far enough to strip a round.

Posted: 8/22/2016 8:23:36 AM EDT

[#7]

I appreciate all of the responses. I have the upper completely disassembled right now. I am going to install a new bolt and gas tube before reassembly.

Posted: 8/22/2016 3:39:20 PM EDT

[#8]

I would try a new ejection spring and an O-Ring on top of that.

Posted: 8/22/2016 4:40:51 PM EDT

[#9]

Quote History

Quoted:
I appreciate all of the responses. I have the upper completely disassembled right now. I am going to install a new bolt and gas tube before reassembly.

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Don't simply replace it. If the nut and//or tube is mis-aligned, you repeat the condition that caused your problem this time.

Posted: 8/22/2016 5:54:17 PM EDT

[#10]

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Quoted:

Don't simply replace it. If the nut and//or tube is mis-aligned, you repeat the condition that caused your problem this time.

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Quoted:

Quoted:
I appreciate all of the responses. I have the upper completely disassembled right now. I am going to install a new bolt and gas tube before reassembly.

Don't simply replace it. If the nut and//or tube is mis-aligned, you repeat the condition that caused your problem this time.

The barrel nut alignment is perfect. I did notice upon further inspection that my gas tube binds some when sliding into the gas key on the career. I took a new tube and it slides easily in and out.

Posted: 8/23/2016 4:36:34 AM EDT

[#11]

That many rounds, nothing wrong with doing a complete spring changeout, like an oil change on your car - service life of around 5k rounds is nothing to be ashamed of. Obviously, something has gotten worn, and needs replacment to get back into spec.

If the spring changeout doesn't do it, we can revisit the issue(s).

Posted: 8/23/2016 7:02:17 AM EDT

[#12]

Possibly some of your issues are being exacerbated by over gassing. 6,000 rounds on a full auto can eat gas port.

I would probably swap all the springs and consider putting an adjustable gas block or restricted gas block on it.

Posted: 8/23/2016 7:49:22 AM EDT

[#13]

The recoil spring is only good for 5000 rounds; I would definitely replace that.

Posted: 8/23/2016 6:01:47 PM EDT

[#14]

Something I found today while studying my problem. I didn't notice it when I disassembled the bolt carrier but the firing pin retainer pin is pretty beat up and bent.

Posted: 8/23/2016 6:12:11 PM EDT

[#15]

I'd replace that, too.

Posted: 8/23/2016 6:15:01 PM EDT

[#16]

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I'd replace that, too.

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Agreed. I am going to replace all the small parts in the gun.

Posted: 8/23/2016 6:23:47 PM EDT

[#17]

At this point, I would just rebuild it with all new parts, no reason not to.

Posted: 8/23/2016 6:30:46 PM EDT

[#18]

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At this point, I would just rebuild it with all new parts, no reason not to.

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That's the plan. Everything minus the lower, upper, barrel, bolt carrier, trigger, and stock/buffer tube is getting replaced.

Posted: 8/23/2016 10:07:10 PM EDT

[#19]

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Quoted:

That's the plan. Everything minus the lower, upper, barrel, bolt carrier, trigger, and stock/buffer tube is getting replaced.

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Quoted:

Quoted:
At this point, I would just rebuild it with all new parts, no reason not to.

That's the plan. Everything minus the lower, upper, barrel, bolt carrier, trigger, and stock/buffer tube is getting replaced.

Good plan, time for a over haul. Post some pics when you got it all out back together :)

Posted: 8/23/2016 10:14:36 PM EDT

[#20]

Quote History

Quoted:
Something I found today while studying my problem. I didn't notice it when I disassembled the bolt carrier but the firing pin retainer pin is pretty beat up and bent.

<a href="http://s300.photobucket.com/user/rccox/media/Guns/C680333B-2E7B-498D-8B77-E530B0580205.jpg.html" target="_blank">http://i300.photobucket.com/albums/nn38/rccox/Guns/C680333B-2E7B-498D-8B77-E530B0580205.jpg</a>

<a href="http://s300.photobucket.com/user/rccox/media/Guns/3F6831E1-A5B9-4332-93E5-85D00B8E1125.jpg.html" target="_blank">http://i300.photobucket.com/albums/nn38/rccox/Guns/3F6831E1-A5B9-4332-93E5-85D00B8E1125.jpg</a>

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Back gas from the suppressor impinging on the firing pin collar?

Posted: 8/24/2016 1:51:15 AM EDT

[#21]

Problem is, you're beating the piss out of your 16 with a suppressor on a standard (gas port) 10.5 in bbl. Not running an H3 buffer doesn't help much either.

Posted: 8/24/2016 2:50:27 AM EDT

[#22]

I would also ditch the spikes buffer and buy a standard H3.

Posted: 8/24/2016 6:45:41 AM EDT

[#23]

I am going heavier than the T2 when I reassemble the gun. I am replacing the carbine buffer tube set up with a Vltor A5 system and will be using a 4.56oz buffer.

The Spikes T2 weighs 4.05oz.

Posted: 8/24/2016 8:30:24 AM EDT

[#24]

The Geissele Super 42 braided recoil spring and buffer is perfect for short barrel guns.

http://www.ar15.com/forums/t_2_444/276485_Geissele_Super_42_Braided_Wire_Buffer_Spring_and_Buffer_Combo.html

Posted: 8/24/2016 12:11:37 PM EDT

[#25]

I have been running the Vltor A5 buffer system with great results. Everything from 10.3 to 20 inch uppers.

Posted: 8/24/2016 12:16:32 PM EDT

[#26]

A5 is the only way to fly.

Posted: 9/3/2016 9:18:06 PM EDT

[#27]

I got it back together today.

I replaced-

The bolt
The firing pin
Gas tube
Firing pin retainer

I also installed a Vltor A5 on the lower while I had the upper apart. Will test tomorrow to see if it's back to working right again.

d

Posted: 9/4/2016 10:17:10 AM EDT

[#28]

Make sure you don't try and put a regular carbine buffer in the a5'tube nit will damage the lower.

Posted: 9/4/2016 10:38:53 AM EDT

[#29]

Quote History

Quoted:
Make sure you don't try and put a regular carbine buffer in the a5'tube nit will damage the lower.

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The buffer tube came with one and I bought a heavier one(A5 specific) which is installed in the gun.

Posted: 9/6/2016 5:54:26 PM EDT

[#30]

Any updates?

Posted: 9/7/2016 3:05:19 PM EDT

[#31]

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Any updates?

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Wasn't able to take it out after repairing due to rain. I will take it out this weekend for a function test.

I am almost positive I had bolt issues.

Posted: 9/10/2016 11:10:20 AM EDT

[#32]

Took it out this morning to test and shot 5 mags out of it. It's back to its full auto glory.

Posted: 9/10/2016 11:16:17 AM EDT

[#33]

Quote History

Quoted:
Took it out this morning to test and shot 5 mags out of it. It's back to its full auto glory.

https://youtu.be/E0mV98lLJNw

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Man, that thing cycles fast.

Posted: 9/10/2016 12:04:53 PM EDT

[#34]

Quote History

Quoted:

Man, that thing cycles fast.

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Quoted:

Quoted:
Took it out this morning to test and shot 5 mags out of it. It's back to its full auto glory.

https://youtu.be/E0mV98lLJNw

Man, that thing cycles fast.

I am somewhat confused by the cyclic rate being faster than before. The A5 buffer I have is heavier than the H2 that was in the gun.

Posted: 9/10/2016 12:56:00 PM EDT

[#35]

As I mentioned earlier, gas port erosion. If you want to cut the cyclic rate without replacing the barrel you can put an adjustable gas block or one of the govnah blocks with a small port you drill to your desired port size.

Posted: 9/10/2016 1:20:58 PM EDT

[#36]

Quote History

Quoted:
As I mentioned earlier, gas port erosion. If you want to cut the cyclic rate without replacing the barrel you can put an adjustable gas block or one of the govnah blocks with a small port you drill to your desired port size.

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I will check into that. I might try a heavier A5 buffer also. I currently have the 4.56oz version and they 3 heavier ones I believe.

Posted: 9/10/2016 2:04:31 PM EDT

[#37]

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Quoted:

I will check into that. I might try a heavier A5 buffer also. I currently have the 4.56oz version and they 3 heavier ones I believe.

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Quoted:

Quoted:
As I mentioned earlier, gas port erosion. If you want to cut the cyclic rate without replacing the barrel you can put an adjustable gas block or one of the govnah blocks with a small port you drill to your desired port size.

I will check into that. I might try a heavier A5 buffer also. I currently have the 4.56oz version and they 3 heavier ones I believe.

Ah. An H2 is 4.6 ozs. If your A5 is only 4.56, then it's about the same weight as an H2.

The new parts may have tightened things up, and that's why it's running faster.

Posted: 9/10/2016 4:34:52 PM EDT

[#38]

Sounds about the same as the 3 that I have, I don't think it is running to fast.

Posted: 9/10/2016 8:56:41 PM EDT

[#39]

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Sounds about the same as the 3 that I have, I don't think it is running to fast.

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It's definately cycling faster than before I am going to slow it down some.

Posted: 9/10/2016 9:48:02 PM EDT

[#40]

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Quoted:

It's definately cycling faster than before I am going to slow it down some.

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Quoted:
Sounds about the same as the 3 that I have, I don't think it is running to fast.

It's definately cycling faster than before I am going to slow it down some.

I can honestly say, that is what a new 16 ran like, I have several brand new ones issued to me while I was in the service and as they wore, they would slow down.