Home > Products > Upper Receivers > .300 AAC Blackout > CMMG >

CMMG AR-15 UPPER Mk4LE 300 AAC BLACKOUT: OPTICS READY, 16" 4140 CHROMIUM (CrMo) NITRIDE (SBN) M4 (30BF85F0)
CMMG AR-15 Upper Mk4LE 300 AAC BLACKOUT: Optics Ready, 16" Nitrided (SBN) 4140 Chromium Moly Steel M300 profile barrel (30BF85F)
CMMG AR-15 Upper Mk4LE 300 AAC BLACKOUT: Optics Ready, 16" Nitrided (SBN) 4140 Chromium Moly Steel M300 profile barrel (30BF85F)


 
List Price: $674.95
Our Price: $599.14
Savings: $75.81
LEFT IN STOCK: 3
Ships from warehouse B: Free Ship

Stock Status:In Stock
Qty:

Description Technical Specs
 
The Mk4LE 300 AAC Blackout Optics Ready model is set up for your favorite scope or red dot sight as it has no front sight base to interfere with the sight picture. It features a nitrided 16” 4140 CrMo steel M300 multi-role profile barrel.

Features
Caliber: 300 AAC Blackout Chamber
Barrel: 16.1" M300/multi-role profile, 4140 Chromium-Moly (CrMo), Salt Bath Nitride Finish (SBN),1:7" Twist
Muzzle: A2 compensator, threaded 5/8-24
Hand Guard: M4 2-piece Hand Guard
Sights/Gas Block: Railed Gas Block
Bolt Group: M16 Bolt Group
Receiver: Forged 7075-T6 aluminum
P/N: 30BF85F
UPC: 815835010823

What is a Salt Bath Nitride-Treated Barrel?
More commonly referred to as nitriding, it's a rifle or upper subjected to a salt bath ferritic nitrocarburizing surface conversion process. The nitriding conversion is applied to the barrel inside and out, along with the front sight base on their LE rifles and uppers. Nitriding offers improved wear, abrasion, and corrosion resistance when compared to hard chrome lining or phosphating.

Unlike chrome lining, where the chrome is built up on the surface, nitriding converts the surface without the risk of dimensional build up. CMMG pioneered the use of this nitriding process on AR barrels and has been using it for many years.

What is an M300 Profile Barrel?
A medium weight contour, the M300 is designed to be the most configurable barrel possible. It has extended and multiple .750” diameter gas block journal locations.

What is an "F" marked forged front sight base as compared to a standard front sight base?
The "F" marked FSB is the correct height sight for a flat top M4 receiver and the detachable carry handle or folding rear sight, compared to the standard front sight base being for use with a fixed carry handle (A1 or A2 upper receiver).

Share your knowledge of this product. Be the first to write a review »