DaemonAssassin
Why should we Free BSD?
In the AR-10 world there is no uniformity from one manufacturer to another. There is no standard in the industry for the AR-10. There are multiple patterns, like the Rock River pattern, Armalite pattern, Fulton pattern, DPMS pattern, SR-25 pattern, just to name a few. The patterns are not interchangeable, so you have to ensure that the rifle is the same pattern, to maintain compatibility with all the components.
What your friend should have done is get the PSA AR-10 lower and then get a PSA AR-10 upper, to ensure that it would be able to work.
