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Discussion Starter #1
I have the SCM model and want to put a UBR stock on it.

Are there any good instructions on how to change the stock on a 556?

A YouTube or pdf with pictures would be great.

Thanks!
 

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Old Glory said:
I have the SCM model and want to put a UBR stock on it.

Are there any good instructions on how to change the stock on a 556?

A YouTube or pdf with pictures would be great.
..if you go to the Magpul website...under rifles...click on UBR...when a new window opens click on the related information button...just in case the linky doesn't work for you...

...here's a PDF with detailed information and install instructions...

... http://store.magpul.com/downloads/ubr-final_web.pdf
 

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...copy and paste Quote from Magpul below...

"NOTE: The UBR includes the necessary Entry-Length Receiver Extension tube and all mounting hardware. An M4 Carbine Buffer and Spring are required for use with the UBR and are not included."

...this is a quote from the Magpul website...everything is included in the package...you DO NOT need the "carbine buffer and spring" when installing the UBR on the Sig 556...the carbine buffer and spring are part of the operating system on an AR...the Sig 556 doesn't have the carbine buffer or spring....it has the recoil spring around the gas piston...

...just a heads up...
 

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Thanks...I got some bad info from Brownells. They sold me the buffer and spring. Will have to send them back.

So all I have to do is unscrew my A2 stock and screw on the UBR?
 

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If you have an SCM model, the UBR stock is most likely not legal where you live (without pinning it). And if you are pinning a $200 stock...why even buy it?

It is also significantly heavier than most stocks.
 

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Old Glory said:
So all I have to do is unscrew my A2 stock and screw on the UBR?
...remove the A2 stock and hardware...remove the rifle length A2 reciever extension...ie buffer tube...then screw in the UBR reciever extention into the reciever...

...the 556 "DOES NOT" have a "buffer retaining pin or a buffer retaining pin spring"...it DOES HAVE the take down pin detent and take down pin detent spring...as pictured in step 2...next to "B"...on the right...

...just follow the instructions step by step...go slow...stop and think about what you're doing...it will all come together...

...remember to put the take down pin detent and detent spring back into the reciever...the detent goes in first...the rounded end pointing towards the take down pin take down pin... slide the take down pin to the closed position with the grove facing rearwards so that the detent will enter the grove...there are two holes in the end of the grove of the take down pin that capture the detent when in the open and closed position...this prevents the take down pin from coming out of the reciever...the rounded end of the detent goes in first so that...while under the force of the spring...it will "kinda" roll over the edge of the hole in the take down pin groove when the take down pin is being opened/closed...
 
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