To continue to flog a dead horse, these units are apples and oranges...
Restricted, harder hitting, range use only Ar-10 vs the non-restricted, softer
shooting, 'go anywhere' Ar-180B....
I have owned both, and currently own neither... I have personally found
alternatives to both that offer the same attributes, in 'packages' that are more
reliable, pleasing, accurate and fun to shoot...
Maybe you need to buy both, as they as different to own and operate as a
revolver and a semi-auto....