Sig 556 with UBR - stock question

[jink122]

I just got a sig 556 with a UBR stock. I want to take the UBR off and stick that on my AR and put my AR CTR stock on the sig. Are there any specific parts I need for the swap or will what i have be enough to just straight swap?

I dont know much about the sig 556 as this is my first, so are the butt stocks universal for the carbines? AR15 to sig.

Thanks for the info!!

[69Mach1]

Simple swap. Of course no buffer or buffer spring is needed in the SIG.

[jink122]

does tue UBR need a a2 buffer and spring or will the CAR work?

[jink122]

69Mach1, Thanks!

[69Mach1]

I'm not familiar with the UBR. I would guess carbine buffer. Also check to see if your buffer tubes are both the same size....mil-spec vs. commercial.

[rareair]

I'm not familiar with the UBR. I would guess carbine buffer. Also check to see if your buffer tubes are both the same size....mil-spec vs. commercial.

UBR accept carbine length spring & buffer.

UBR uses it's own proprietary buffer tube, not Mil or Com spec


Here's what my SIG 556 rifle looked like before I installed a 551 conversion on it. With UBR stock

[jink122]

Thanks rareair. Im gonna do some work on this this weekend.

[rareair]

Another option to consider would be to use a stock from a SIG 551 rifle. Gives the 556 a whole new look