I have seen on the internet that a Knights SR-25 upper will fit and swap with a LMT MWS upper and a LaRue OBR Upper? Are they all the same dimensions of uppers and lowers?

I thought that Knight's had a patent to the upper? Does that not cover the dimensions of the LMT and LaRue stripped upper receiver?

If Knights does then have a patent, are the dimensions of the stripped upper then property of Knights? How can LMT and LaRue manufacture their receivers?

There are three classes of 308 uppers that I am aware of

Armalite

Knights/LMT/LaRue -All 3 companies use the same dimensions for their upper receivers?

DPMS

Other brands.

It would be great if there could be a list or "Chart" that is constantly updated with the new info for .308 ARs such as the new Ruger offering to determine what patterns the guns are based off of and whether their parts are interchangeable. Thanks everyone for their input.