What Lower Receiver should I use?

Our UPR-15 uppers are compatible with any “Mil-spec” lower receiver.


Our UPR-10 uppers are DPMS GEN 1 LR-308 pattern and are compatible with any other lower of that spec.

To see a list of known compatible and non compatible UPR-10 lowers, click on Shop>Guns>UPR10>scroll down to just below the add to cart button>click the Lower compatibility tab.

In regards to Aero Precision M5 lower receivers, our UPR10 upper will mount and function on them. However, Aero uses the AR-308 pattern which is slightly different from the LR-308 pattern that we use. The difference in spec results in a  “gap” larger than we would like to see, at the rear radius ( where the lower curves, for the buffer tube hoop). The gap does not cause accuracy or functionality issues, it is just not as aesthetically pleasing as we would like.