SIG Sauer 556 Arms Forum banner
1 - 12 of 12 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
I have a Sig 556 SCM that I'm finally getting around to wanting to replace the default A2 stock. I see that I need an adapter for this, and obviously Sig no longer sells them. The ones on DDLES are out of stock as well. Looking to buy an adapter that will fit my Sig so I can replace the stock with something aftermarket. I live in MA so I need fixed/pinned stock options. If the stock adapter folds, I need to be able to pin/lock it and then add a fixed stock to it. Appreciate any feedback on this.
 

·
Registered
Joined
·
325 Posts
The SCM just has an A2 USGI stock. Simply replace the A2 length tube with an AR carbine buffer / end plate / castle nut, and stake. Then add whatever stock you want. Just be mindful of what buffer tube outside diameter you purchase (milspec or commercial). As you will need to match your AR stock type accordingly.
 

·
Registered
Sig556ER; 551 HG; UBR stock w/MDT FSA; MFI rail/rear diopter; 550 FS; Versa-Pod bayo lug mount
Joined
·
89 Posts
LKY13 is 100% correct. U shouldn't need any adapters. It's just a simple change of stock & buffer/buffer spring. I just feel that it's my duty as a Constitutional supporting, 2A advocate that 1st & foremost, ur primary focus should be on which stock YOU like, & WANT to get. Then worry about "compliance" later. That's just my opinion though.
Here are a couple stock suggestions that I think are great for ur style Sig. 1 stock that I know is great, cuz I currently use it on my Sig 556Er which also has an M4 style lower just like urs, is the Magpul UBR. Not only is it prolly 1 of the best stocks made as far as quality is concerned, but is also a perfect choice for the Sig 556 since it's a very heavy M4 style stock. Normally this isn't something u look for in a collapsible/M4 stock, but since the 556 is a very front heavy rifle, the UBR balances it out almost perfectly. I've read of people putting things in the storage area of their stocks, like rolls of nickels, to add weight to the rear of the rifle. The UBR achieves this on its own. Also, the UBR comes with proprietary hardware, everything u need to mount it to ur lower. No need to buy seperate receiver end plate (backplate), Castle nut, or receiver extension (buffer tube).
If the UBR isn't ur style, the Fab Defense GL-CORE is a great choice also. It comes with a detachable, adjustable cheek riser that can be very useful for keeping a solid cheek weld if u ever plan to use a mid-long range scope & needs high rings to clear the rear back up iron sight. Those are 2 great stock choices for Sig556's like urs that have M4 lowers. & they both come in black, OD green, or FDE.
Like LKY13 already stated, there are 2 things to keep in mind when u do decide to change out ur stock. 1st, Ur Sig has a rifle length buffer & buffer spring in it right now cuz of the A2 fixed rifle stock, so u will need to buy a carbine buffer & buffer spring. U can't use the ones u have in ur rifle now with a carbine/M4 style stock. 2nd, if u decide against the UBR, make sure when u buy ur new stock that u pay attention to what size receiver extension (buffer tube) the stock is made to fit so u don't buy the wrong one. Stocks are made to fit either commercial or Milspec size buffer tubes. Milspec being more common & IMO, is the size u should get if u have the choice. Just makes swapping out stocks easier if u decide to down the road. Also, Milspec is supposedly the stronger of the 2.
Good luck. & remember that ur customizing ur rifle to make it more practical & functional, but also cuz u enjoy doing it & our 2A right guarantees u that freedom. Focus on making ur rifle function better & safer for u to use, & have fun while ur doing it.
Semper Fidelis.
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #4 ·
Thanks for the replies. Per LKY13, I ordered a carbine milspec buffer kit and a MagPul fixed milspec stock that I will try and swap out when everything arrives. Appreciate the responses to my question
 

·
Registered
Sig556ER; 551 HG; UBR stock w/MDT FSA; MFI rail/rear diopter; 550 FS; Versa-Pod bayo lug mount
Joined
·
89 Posts
Of course, you won't need that buffer spring since it's a Sig 556 with it's piston gas system.
OMG, I'm such a retard! Lol! Well, ty for the correction...I'm thinking I'm giving this guy some good, detailed advice, meanwhile he's prolly like " what's this idiot talking about", lololol...sry bout that smarty85!
 

·
Registered
Joined
·
4 Posts
Discussion Starter · #7 ·
Appreciate the follow ups. So I don't need to use the spring or recoil buffer/counter weight from the kit I bought when I go to swap out the buffer tube? Waiting for the stock to come in today to see how it all goes together
 

·
Registered
Sig556ER; 551 HG; UBR stock w/MDT FSA; MFI rail/rear diopter; 550 FS; Versa-Pod bayo lug mount
Joined
·
89 Posts
Appreciate the follow ups. So I don't need to use the spring or recoil buffer/counter weight from the kit I bought when I go to swap out the buffer tube? Waiting for the stock to come in today to see how it all goes together
Right, disregard everything I said about thee buffer & buffer spring, sry about that. I've been working on 2 AR builds lately & just had Direct Gas Impingement stuck in my brain. The Sig 556 uses a long stroke gas system, similar to an AK47, which doesn't utilize an AR15 buffer system. So, again, no need to worry about buffers & buffer springs, sry if I confused u in any way. Whatever AR15/M4 stock u got, it will still fit & function just fine on ur Sig. If u bought a buffer & buffer spring already, u can either return em, sell em, or keep em for a future AR15 project.
 
1 - 12 of 12 Posts
Top