Suppressed SBR issues - Page 1

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[ARCHIVED THREAD] - Suppressed SBR issues

Posted: 1/25/2015 12:49:42 AM EDT

Guys, I have an 11.5" 5.56 that runs flawlessly unsuppressed. My suppressor came in two weeks ago and I finally got to take it and shoot a bunch this weekend. When shooting the SBR suppressed the bolt seems to get locked up and won't eject the spent case. While shooting I had a hell of a pop around the handguard by the gas block that more seemed like a small blowback as I felt some pressure on my hand.
Will going with a adjustable gas block fix these issues? Is the BCG not lubed enough? Just curious where to start troubleshooting.

Posted: 1/25/2015 1:18:51 AM EDT

[#1]

Few more specifics will help, like specific upper, gas block, buffer weight, BCG etc.

Posted: 1/25/2015 3:06:47 PM EDT

[#2]

Pictures would help.
Did you inspect the gas tube for cracks or rupture?
Did you inspect the gas block, ensure its in the correct position?

Posted: 1/25/2015 6:33:02 PM EDT

[#3]

Sorry guys, been hunting all day.
I put the upper together. It's an 11.5" barrel, low profile carbine gas system, standard BCG, carbine buffer.
I'll get some pics tonight when I get it apart.

Posted: 1/25/2015 11:11:15 PM EDT

[#4]

overgassed with the can on. Need an adjustable gas block or might be able to fix with a stiffer buffer spring and heavier buffer.

Posted: 1/26/2015 4:27:20 AM EDT

[#5]

Sounds like your gas tube customized itself.

Posted: 1/26/2015 12:13:15 PM EDT

[#6]

Quote History

Quoted:
Pictures would help.
Did you inspect the gas tube for cracks or rupture?
Did you inspect the gas block, ensure its in the correct position?

View Quote

The tube looks good but I'm going to pull it out and have a closer look today. I'll run some air down the tube to ensure good flow as well.

Just using a standard spring and buffer, this might be a bad idea but I'm not certain. I'd appreciate any further suggestions. I'm usually pretty good at getting these to run well but throwing in a suppressor in the mix is a new variant I'm not certain about.

Posted: 1/26/2015 12:28:10 PM EDT

[#7]

probably be best to go with an h2 or even heavier buffer suppressed. Also change the gas block to an adjustable, so you can fine tune it, I have 7 SBR's that I run suppressed. all have heavy buffers and run 100% suppressed/unsuppressed.

Posted: 1/26/2015 12:53:18 PM EDT

[#8]

Quote History

Quoted:
probably be best to go with an h2 or even heavier buffer suppressed. Also change the gas block to an adjustable, so you can fine tune it, I have 7 SBR's that I run suppressed. all have heavy buffers and run 100% suppressed/unsuppressed.

View Quote

I have some questions about this. Do you have to change the settings between suppressed and unsuppressed or are you able to set and forget? Also, if you're able to set and forget do you set it with the van on and then it works fine without?

Posted: 1/26/2015 1:05:19 PM EDT

[#9]

Quote History

Quoted:
probably be best to go with an h2 or even heavier buffer suppressed. Also change the gas block to an adjustable, so you can fine tune it, I have 7 SBR's that I run suppressed. all have heavy buffers and run 100% suppressed/unsuppressed.

View Quote

I'm pretty sure I am running an H2 Heavy buffer. Would the one in this picture be marked to say if it was H2 Heavy?

Posted: 1/26/2015 1:30:06 PM EDT

[#10]

My colt h2 is marked

Posted: 1/26/2015 1:30:24 PM EDT

[#11]

I run H2 buffers in all my SBRs without adj. gas blocks. Never had a problem.

Posted: 1/26/2015 1:33:00 PM EDT

[#12]

Quote History

Quoted:
I run H2 buffers in all my SBRs without adj. gas blocks. Never had a problem.

View Quote

Makes me think the gas block and tube might be obstructed. I'll get into it this evening. If it makes a difference I'm running this with a full size .30 cal can.

Posted: 1/26/2015 1:51:10 PM EDT

[#13]

Look at the face of your Buffer. If there are no marking then you have a standard weight buffer. If there is a 2 or H2 it has 2 tungsten weights in it. My guess is that you are over gassed. My 11.5 Is the same way. Runs 100% un suppressed and is overgassed supressed.

You can do the following to help it run the way it should.
1. Add more weight of the buffer, Try and H3 buffer of increase the weight of the spring.
2. Get an adjustable gas system, either Block or Gas Key.

I am going with an Adjustable Gas Key, My gas block is pinned. I plan to set the gas when it will barely lock back on an emply mag unsuppressed then you should be good to go suppressed with out over gassing it.

MAHA

Posted: 1/26/2015 2:39:21 PM EDT

[#14]

Quote History

Quoted:
Look at the face of your Buffer. If there are no marking then you have a standard weight buffer. If there is a 2 or H2 it has 2 tungsten weights in it. My guess is that you are over gassed. My 11.5 Is the same way. Runs 100% un suppressed and is overgassed supressed.

You can do the following to help it run the way it should.
1. Add more weight of the buffer, Try and H3 buffer of increase the weight of the spring.
2. Get an adjustable gas system, either Block or Gas Key.

I am going with an Adjustable Gas Key, My gas block is pinned. I plan to set the gas when it will barely lock back on an emply mag unsuppressed then you should be good to go suppressed with out over gassing it.

MAHA

View Quote

How can you tell when it will barely lock back on an empty mag? Do you just adjust it a little bit at a time until you dial it in?

Posted: 1/26/2015 5:54:27 PM EDT

[#15]

Quote History

Quoted:
Sounds like your gas tube customized itself.

View Quote

Ding ding ding, I think we have a winner! I tore it down and the block and tube were loose. I got everything tightened back up and used a touch of loctite on the set screws to keep them from backing out. Hopefully that solved the issue.

Posted: 1/29/2015 12:14:55 AM EDT

[#16]

Quote History

Quoted:
How can you tell when it will barely lock back on an empty mag? Do you just adjust it a little bit at a time until you dial it in?

View Quote

Most turn the gas off then slowly open it till it runs 100%, add a 1/4 to 1/2 turn. Then lock it down.

MAHA

Posted: 1/29/2015 9:43:12 AM EDT

[#17]

Quote History

Quoted:
[div style='text-align: left;']

Most turn the gas off then slowly open it till it runs 100%, add a 1/4 to 1/2 turn. Then lock it down.

MAHA

View Quote View All Quotes

View All Quotes

Quote History

Quoted:
[div style='text-align: left;']

Quoted:
How can you tell when it will barely lock back on an empty mag? Do you just adjust it a little bit at a time until you dial it in?

Most turn the gas off then slowly open it till it runs 100%, add a 1/4 to 1/2 turn. Then lock it down.

MAHA

I'm hoping it was the gas block being loose. If not I will try the heavier buffer and the the adjustable key as it is much cheaper than the adjustable block.

Thanks for the input guys.

Posted: 1/31/2015 2:47:51 PM EDT

[#18]

I use red loctite on my gas block screws. I have a little butane silver solder torch i use on the bolts if i need to loosen them. It isn't hard at all to remove them after heating.

Posted: 2/9/2015 8:47:05 AM EDT

[#19]

I finally got to get out and shoot this weekend. It was the lose gas block that was causing the issue.

Posted: 2/10/2015 8:09:43 AM EDT

[#20]

That was an easy one to diagnose. You felt a pop under the handguard and then the rifle started acting like it was undergassed.

Posted: 2/10/2015 8:39:39 AM EDT

[#21]

Quote History

Quoted:
That was an easy one to diagnose. You felt a pop under the handguard and then the rifle started acting like it was undergassed.

View Quote

Agreed and I obviously see it now. I was just throwing a new component in there(suppressor) and didn't know if I was getting back pressure from the suppressor since it is under the hand guard.

Posted: 2/10/2015 7:09:36 PM EDT

[#22]

That is why I went with the innovative arms WAR upper. You adjust the gas for suppressed or unsuppressed by flipping a switch.

[ARCHIVED THREAD] - Suppressed SBR issues

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