You need the services of a CNC machinist.
Average is around $350. If you are looking for a stripped lower receiver, the price should hang around $100.
Variant of the AR-15 manufactured by Colt. It had a 'slab side' lower and no forward assist.
Mill
Yes, it will, but then it would be in an SBR (short-barreled rifle) configuration, and would be a violation of federal law if the lower receiver is unregistered.
Try AR15.com Try AR15.com
If it is one of the recent Colt .22LR AR15 rifles, then the answer is no - they are completely different internally.
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
On the AR15/ M16, the spring is retained by the buffer. The buffer is retained by a pin located at the lower outer edge of the extension tube.
By it's serial number. Go to www.proofhouse.com and under 'long rifles' listing look for AR15 Sporter