Colt, Bushmaster, LMT, Stag
Make AR15 parts and rifles
If it is one of the recent Colt .22LR AR15 rifles, then the answer is no - they are completely different internally.
Double Star and CMMG's bargain bin rifles. Some DPMS rifles, as well.
By it's serial number. Go to www.proofhouse.com and under 'long rifles' listing look for AR15 Sporter
From 2013-2015 it has been the AR15.
Les Baer Custom S.R.P. Semi-Automatic Pistol
clardy was
Depends on the rifle- some do not HAVE a bolt catch. On the AR15 family of rifles, it is the left side of the receiver.
Don't think so: laws here say you can't have EVEN semi-auto rifles. Let along full-autos.
No, but American Firearms and Tromix have made upper receiver for AR15 rifles and carbines chambered in .50 Action Express.
50-225 usd
Without resorting to these crappy cast receivers (such as Hesse/Blackthorn), the cheapest assembled rifles are going to be the 'bargain bin' rifles from CMMG. If you're looking to build one, Del-Ton had the cheapest complete build kit (minus the lower) at $450.