Sure, it's possible, but ultimately pointless. The .22 LR is a much shorter projectile than a 5.56 or .223 projectile, and if you tried running such a cartridge through a 5.56 or .223 chamber, you wouldn't get proper headspacing from it. The end result would most likely be a catastrophic failure of the weapon which could injure or kill the firer or others.
If it is one of the recent Colt .22LR AR15 rifles, then the answer is no - they are completely different internally.
No.
No, but American Firearms and Tromix have made upper receiver for AR15 rifles and carbines chambered in .50 Action Express.
That's a smoking deal on the Mosin-Nagant. That's the one I'd go with.
The typical AR15 fires the same type of bullet as the M16: a .223 caliber (5.56mmx45mm NATO) round. There are AR-15 rifles that have special barrels made for a variety of popular cartridges, even the little .22LR.
An AR-15 is a rifle that uses 5.56 mm bullets. It is a semi-automatic rifle. This specific type of bullet is the most commonly used bullet amongst the NATO forces.
Try AR15.com Try AR15.com
1959
Yes
The US Army presently uses the M4 carbine, a shorter and much modified version of the Armalite AR15.
Colt has not offered a AR15 in 308
By it's serial number. Go to www.proofhouse.com and under 'long rifles' listing look for AR15 Sporter