Successfully installed a new UBR.  Hardest part was buying the proper tools.
I get the stock on, and I see this spring lying on the seat of a chair near the box that my UBR came in.
It is not my buffer detent spring, but appears to be roughly the same size (I didn't unscrew the new buffer tube to see if is exactly the same as my spring).

Any ideas?



Couldn't resist using the 20 round PMAG as a backdrop.

looks like the buffer retainer spring... maybe they sent you an extra?

Quoted: looks like the buffer retainer spring... maybe they sent you an extra?

The first thing I did was call Magpul.  Doug said that, while anything is possible, he wasn't aware of Magpul intentionally including extra springs.  

Quoted: Quoted: looks like the buffer retainer spring... maybe they sent you an extra? The first thing I did was call Magpul.  Doug said that, while anything is possible, he wasn't aware of Magpul intentionally including extra springs.

Someone, somewhere is cussing because he is missing a spring.

Just outta curiosity, what are the required tools?  I have a stock wrench... isn't that all you need?

You need a stock wrench, you can use a torque wrench to torque the tube to the recommended setting (i did, just cause I bought the damn thing) and a flat-head screw driver.  Having access to a vice made removing the LMT-staked castle nut a breeze.
If you want to "set" the UBR to deploy to a certain setting, or if you want to remove the doors, you'll need allen wrenches, and that's it.

It is actually pretty easy- if I had it to do over again, I'd have taped the tube wrench section of my stock wrench with duct tape, as the nut-portion of the tube sustained some marks, but otherwise (other than possibly, the fact that a spring may have sprung from the UBR, as unliely as this may be) you'd never know that it wasn't professionally installed.  

Hm..... not that I think about it, I should probably have asked the seller about the spring....

What?  Yours had springs?  I have to go pick up Buffer Retaining Pin/Spring, Takedown Pin Spring and Detent, Carbine Buffer and Action Spring.  This was my first AR, so I didn't have any of these laying around or left over.  =-/