Colt M4A1 R0921 SOCOM Prototype Upper w/ Bolt & Carrier Assembly, 14.5" 1/7 CL BBL, Carry Handle, Troy Rail, SureFire SF3P Flash Hider, 5.56X45 NATO *Excellent / Blemished / IN BOX*

Colt M4A1 R0921 SOCOM Heavy Barrel Prototype Upper with bolt and bolt carrier assembly plus charging handle, 14.5" long 1 in 7 twist Chrome Lined barrel, Carry Handle Attachment, Troy Picatinny Rail Handguard, Surefire SOCOM SF3P Flash Hider Suppressor Adapter, 5.56X45 NATO, *EX / Blemished / In Box* B-Model

Sold Individually.

This was a prototype the factory built while working on the Colt M5.
Colt manufactured flat top upper receiver with carry handle and Socom heavy profile barrel.
M4A1 SOCOM heavy profile barrel with M203 flats, M4 feed ramps and chrome bore (1 in 7 twist).
Surefire SF3P 3-prong flash hider / suppressor adapter, for use with all SureFire SOCOM Series sound suppressors.
The flash hider is NOT permanently attached.
SOCOM heavy profile barrel is marked 13629 MP 5.56 NATO 1/7, muzzle is threaded 1/2X28.
1 in 7" Twist Rifling is capable of stabilizing light to medium weight projectiles of up to about 77 grain.
Includes TROY quad rail picatinny handguard, with some small scuffs and marring from factory wear.
Receiver and M4 carry handle (with rear sight) marked with Square forge marking.
Light handling on upper receiver and handguard.
This upper was fired at the factory and has passed all safety and testing conditions.
Packed in factory box (pictured)

This Upper Assembly includes:
- Colt manufactured M4 type flat top upper with case deflector and forward assist assembly.
- SureFire SF3P SOCOM series Flash Hider Suppressor Adapter, 1/2x28 muzzle threading.
- Colt manufactured 14.5" SOCOM heavy profile barrel, 5.56 NATO with M4 feed ramps and 1 in 7 twist rate.
- MPC marked bolt and chrome lined carrier assembly with charging handle.
- Colt M4 carry handle assembly with adjustable A2 rear sight.

NOTE: Prior to installing this length of barrel into a rifle a NFA Form 1 must be completed and returned approved.
A 14.5 Inch length barrel installed into a shoulder fired firearm is a "Short Barreled Rifle" under the NFA. 

Parts must be inspected and tested by a qualified and competent gunsmith or armorer before use in a firearm.
Not all firearm parts are interchangeable; use of new parts without proper knowledge could cause a firearm to malfunction and cause property damage, injury or death.

Colt Part #: R0921CK B-Model BLEM