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Discussion Starter · #1 · (Edited)
Update!

I now have options for those looking to suppress their Sig 556R's




I am putting up this thread to see if there is any member interest in a group buy service for having your Sig556 gas valve redrilled with smaller ports to reduce receiver wear and reduce brass denting/damage.

Recently received a new P556 that will be the host for a SBR project. Took it out to the range and it is clearly over gassed; it is destroying brass and ejecting over 35'. So I am now in the process of tooling up to drill the gas valve with more appropriately sized ports.

Update!
Alright folks, here are the order forms.

I need one of these filled out for each member who would like one of these improved valves.

Directions are pretty self explanatory. After completed, please email the form to the email address written on the bottom of the form.

Payment will not be required until I get closer to getting these mailed out.

Please include your forum username in the email so that I can keep track of everyone.

If you are unable to print, fill out, and rescan the form, just type out the information into an email and send it to me. That will suffice; just do not forget any details!

Cheers!
Chris
 

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Interesting. Is a smaller gas hole the only way to achieve this?
 

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Discussion Starter · #3 ·
Basically. The holes that are drilled to make the gas ports on the gas valves directly control how much pressure is allowed into the gas tube. And that pressure is what controls how fast the action cycles on the rifle. Over gassing the system causes the action to cycle faster than needed, dents/destroys your brass, and causes the bolt carrier to slam into the back of the receiver with much more force.

Here is a previous post detailing the issue and a member in Europe who was working on the same solution:
http://www.sigarms556.com/threads/my-sig-556-is-denting-almost-a-cutting-every-case.12615/
 

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Discussion Starter · #6 ·
I am looking at different options for obtaining some factory valves so that people could buy a finished part, instead of sending there's in to be drilled. Once I know the price on the valves, I'll have a better idea.

MrMcCrakin: Yes that would be an option
 

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I really like this, and think it should be done, but not to my one and only valve. I would pay handsomely for another valve drilled to spec, and for suppressed.
But putting up my one and only is a risk I may not wish to take. Not because I don't trust the work, but I don't trust the delivery system. If I could hand deliver I would. Otherwise, I would need to have a valve for a valve. Sorry to be this way, but I cling to my God and my guns. My upper already got lost in the mail once.
 

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I'm in. The OP was about P556. I would expect that to be over gassed if rifle gas ports are used. Is this valve option for 556 Classic (5.56) also? Thats what I have.
 

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Discussion Starter · #12 ·
I will be able to make these for any Sig 556. If you have a Patrol, SBR, or Pistol I plan on making the ports another 0.1mm smaller in order to deal with the elevated pressures. So the Classics will be no problem at all lamscotticus.
 

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Discussion Starter · #14 ·
Okay, a deal was struck for some Sig SAN gas valves! (at a small fortune I might add).

It looks like a preliminary price is going to be $160 shipped. Now between waiting on the parts to show up, acquiring the tooling, and leaving some time for me to test, a conservative time line is looking like 4-6 weeks right now.

In the mean time, if I can generate enough interest and get some more people to commit to the project, I should be able to get the price down a bit. Also if there is enough interest, I may be able to set up a "core charge" type deal. That way it will be cheaper for people who decide not to keep their original valve, but gives them time to test before committing to giving up their old valve.

If you are interested, please make a post on the thread so that I can keep track of where we are at.
 

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Discussion Starter · #15 · (Edited)
I should add that these will be made to order, so you can choose how you would like the valve to be set up.

Sig SAN 553 small port: 1.2mm (0.047")
10" 1/7" twist large port: 1.3mm (0.051")
4 Position suppressed 0.8mm (0.031")
off 0.0mm

Sig SAN 551 small port: 1.3mm (0.051")
1/10" twist large port: 1.6mm (0.063")

Sig 556 Pistol small port: 1.28mm (0.050")
large port: 1.35mm (0.053")


My thoughts are:

Sig 556 SBR, small port: 0.90mm (0.035")
Patrol, Pistol, large port: 1.00mm (0.039")
Sig Classic suppressed: 0.80mm (0.031")


Also instead of a small and large port, a "suppressed" or "off" setting would be available.

Chris
 

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Discussion Starter · #18 ·
I would be interested in a factory original 4 position for my SAN 553. Is that an option?
They are not available for purchase. But I could look at getting the proper two position gas valve for the 553 and could modify it into a 4 position for you if you'd like.

PM me if interested; I would need to special order that part.
 
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