I'm building my first AR as a .308 any tips to prevent me from ordering useless parts?
Stick to same brand upper and lower. Make sure your BCG is set up for the proper upper like a DPMS or an Armalite. Make sure you get a 308 buffer/spring set up not one for an AR15. If it's threaded make sure it's 5/8"
Oh yes. Br prepared for a beating in the pocketbook for quality parts and your shoulder at the bench.
The best firearm for self defense? Any loaded one will do.