Gunsmithing Anyone re-barreled a Sig 556?

[ShooterwithNoName]

I'm wanting to re-barrel a Sig 556 with a longer barrel. I know about the DMR but I want one with a faster twist rate and tighter chamber, maybe .223 Wylde. I posted it here in gunsmithing hoping to attract a smith who has done one before. Or find someone who has had it done that could refer me.

Here's what I'm looking to do:

-Chrome Moly .224 Blank, Douglas or similar.

-Cut to 21" with a target crown, no threads. Straight contour from gas block forward and tapered from the gas block back.

-1-7" or 1-8" twist. Either .223 Wylde or tight 5.56 NATO chamber.

-Standard Sig 556/551 mid length gas system.

-I will need the action threads cut and fitted to the Sig upper. I will also need the gas block fit and matched up to the port.

The Sig DMR has a 1-10" twist which I really need a faster twist since I want to utilize the heavier .224 bullets for longer range. So if anyone has swapped barrels on one of these before please let me know. Any helpful info such as measurements, thread pitches, or anything that would help lay out a barrel for this rifle would be greatly appreciated.

Thanks for reading.

 

[ShooterwithNoName]

Re: Anyone re-barreled a Sig 556?

I wanted to post a little more info on this swap. The Sig 550/1/2 will not work in the US Sig 556 rifle trunions since the Swiss 550/1/2 barrels and trunnions have timed threads and the US Sig 556 does not.

This is a moot point in my case since I'm looking at having a new barrel made and the gas port can be drilled after the barrel has been torqued. But it's something to consider if anyone considers doing this.

Of course a receiver wrench/holder would be required to break the old barrel loose and torque the new one. CGS sells receiver wrenches and it may be just as cheap to cut a set.

If anyone has any specs like the receiver thread pitch, dimensions, etc. I am interested. I can take the measurements myself but I'll need to know the thread specs and dimensions where the barrel threads into the receiver.