It all starts with a $10 stock wrench from Amazon:
…note it includes the carbine castle nut wrench (far left) and rifle tube wrench (middle.) We’ll need both.
Get your ghetto vice and stick a short 2×4 in it. Trim the 2×4 so the AR-10 mag-well fits in it.
Now, with the spousal unit holding the un-mounted ghetto vice, turn the castle nut and remove the carbine buffer tube:
Now install the Magpul UBR buffer tube:
Now install the UBR top stock with the cheek piece. Simply slide it on and install the screw at the back of the cheek piece that goes into the receiver extension:
Install the bottom stock:
Here’s a closeup of the AR-10 carbine vs UBR receiver extensions:
Here’s the rifle with the UBR installed:
The result is a vastly improved cheek weld and handling of the rifle. The collapsible stock left a wobbly feeling when aiming. The UBR gives the feel of a solid wooden stock without losing the extensible stock feature.
It’ll likely be standard equipment on any AR rifle I buy/build.