All complete uppers include:

M4E1 Threaded Upper Receiver
ATLAS S-ONE Handguard - some configurations have length options
CMV Barrel - choice of length and gas system
Barrel option - pinned and welded VG6 Epsilon 556SL option available with 14.5" Black Carbine and Mid-length configurations
Low profile gas block and gas tube to suit barrel
This complete upper does not include a BCG or Charging Handle

M4E1 Threaded Upper Receiver Features:

New enhanced forging that gives the upper receiver a "billet look"
New picatinny profile that blends seamlessly with the Enhanced Series Handguards
M4 Feedramps
.250 takedown pin holes
Laser engraved T-marks
Includes port door and forward assist installed

ATLAS S-ONE Handguard Features:

Front and rear picatinny rail
Eliminated center of top rail for weight reduction
Indexing grooves in 12:00 position for positive grip control
Quick disconnect sling socket at the 3, 6 and 9 o'clock positions
Compatible with low profile gas blocks
1.3” Inside diameter
1.5” Outside diameter
Compatible with mil-spec AR15 upper receivers and barrels

5.56 Barrel Features:

Chamber: 5.56
Twist: 1 in 7
Threading: 1/2"x28
Material: 4150 Chrome Moly Vanadium
Finish: QPQ corrosion resistant finish
Gas Block: .750 (note exceptions below)
Gas System: some barrel lengths have choice of gas system
M4 Barrel Extension
HP and MPI Tested


14.7" barrels can be pinned and welded with a standard A2 flash hider to yield an overall length of 16+"
14.7" Pencil profile barrels require a .625 diameter gas block
14.5" barrels with a pinned and welded VG6 Epsilon 556SL yield a 16+" overall length
The VG6 Epsilon 556SL has a .745" outside diameter, permitting full maintenance and removal of your gas block without having to remove the muzzle device

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