Recommended Smiths to cut down MR556 barrel, and fix the gas block.

[ARCHIVED THREAD] - Recommended Smiths to cut down MR556 barrel, and fix the gas block.

Posted: 4/5/2021 2:21:03 PM EDT

I have an MR556 upper which I want to convert to a SBR 11” upper that I can run with a can. I have a BRN-4 lower that I have engraved to 416 specs, which I can run as a pistol, until the Form 1 is approved. I am looking for a competent gunsmith to cut and thread the barrel to 11” and do the required work on the gas system to make it work.

Thanks in advance

Posted: 4/5/2021 2:29:04 PM EDT

[#1]

Adco has done several for me. Fast.

Posted: 4/5/2021 2:30:01 PM EDT

[#2]

ADCO.

Posted: 4/5/2021 3:47:09 PM EDT

[#3]

Not sure ADCO can do anything with the gas block, but if you're going to run it 100% suppressed....the gas block should be fine as is.

Posted: 4/5/2021 4:55:46 PM EDT

[#4]

Quote History

Quoted:
Not sure ADCO can do anything with the gas block, but if you're going to run it 100% suppressed....the gas block should be fine as is.

View Quote

Thanks to all for the input. The intent is to have the ability to run suppressed.. Not run 100%. I makes sense that I could use the same block if I was running 100% suppressed.. I guess the 16" hole is smaller but a can increasing the gas/ back pressure (what ever the right term is) to actuate the piston.

Posted: 4/5/2021 5:08:38 PM EDT

[#5]

Quote History

Quoted:

Thanks to all for the input. The intent is to have the ability to run suppressed.. Not run 100%. I makes sense that I could use the same block if I was running 100% suppressed.. I guess the 16" hole is smaller but a can increasing the gas/ back pressure (what ever the right term is) to actuate the piston.

View Quote

You can keep the original MR556 gas port and weld the vent hole in the gas block. That will get it running non-suppressed and suppressed. It will just be more violent and gassy than they already are.

Posted: 4/14/2021 11:03:11 PM EDT

[#6]

Lots of gas block drama, I’ve never had an issue with 10.4 and SDN6 with closed gas port or small hole

And ADCO

Posted: 4/17/2021 12:21:47 PM EDT

[#7]

I had a spare MR556 upper hanging out in my safe that I got pre panic prices. Instead of cutting the barrel I chose to get a light profile Nefarious Arms HK 10.4 clone. They are chrome lined. Also picked up a 10” gas block. That might be an option too.

[ARCHIVED THREAD] - Recommended Smiths to cut down MR556 barrel, and fix the gas block.

Armory » Heckler & Koch

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