YES REMINGTON FIREBALL , OLD PRODUCTION. Also, a number of companies make AR pistols in .223.
222, 223 and 9mm
Yes
5.56 and 223 cal. are the same cartridge...........
Yes it does, unless your barrel is stamped .223 .
Colt has not offered a AR15 in 308
DPMS doesn't make an AR-15 - AR-15 is a copyright of Colt Firearms, and thus, only they and companies licensed by them to manufacture the rifle can actually call it an AR-15. As for their AR-pattern rifles, they typically come with a 5.56x45mm chamber, which is also capable of handling the .223 Remington.
if it is a 223 cal, then yes
If it is one of the recent Colt .22LR AR15 rifles, then the answer is no - they are completely different internally.
600-1200
100-500 USD or so
.223