I love the Magpul UBR Gen II stock, adjustablilty with absolute tight lock up after moving the stock in or out. And an amazing amount of LOP adjustment which I desperately need with my gorilla length arms.

But it does have one large drawback. Anyone who shoots long range, prone or off of a bench understands how important a rear support bag can be. While the UBR can be supported on a bag, it does not work well.

A little inspiration and a solution was found. While several manufacturers make Bag Riders, no one makes one for the UBR. The 4AW store in Australia does make a really nice one that you should be able to adapt….

My solution was pretty simple since I already had all the materials sitting in my shop. Just a simple rectangular piece of aluminum, one bolt to hold it on and a screw that acts as an anti rotation pin.

I made a nut for the bolt out of UHMW plastic that I am still working on, not sure if I want to refit the storage compartment back into the stock. It’s handy for ear plugs but I kind of like the open look myself.

Yes your are going to have to drill into a rather expensive butt stock but for myself it is well worth it. You also need to create a flat area at the location the bag rider mounts as the stock is not very flat where the two molded halves come together.

Eventually I will get it Cerakoted but for now some spray paint had to do.