Centurion C4 M-LOK Rail with Mid-Cut FSB 

a unique combination of old and new and for mid-length gas systems

Centurion Arms has been making high quality rail systems for years, and as shooters have moved from quad rail to M-LOK, Centurion has adapted.  Then, shooters rediscovered the front sight post and were creating their own cut-outs of popular rail systems.  Centurion now makes a hybrid old school FSB rail, but for mid-length gas systems, which are very popular with 14.5" to 16" barrels, and M-LOK for light weight and versatility.  Who said an old dog cannot be taught new tricks?  Well, Centurion has been adapting to new ideas since it started.  The Centurion Mk12 is probably the first and most famous of ideas.  Founder, and former Navy SEAL, Marty LeClair, developed his modified version of the historic Mk12 rifle to be what he would have wanted to have, as a SEAL sniper.  So, it is not surprising that Centurion Arms now brings us FSB cut-out, M-LOK features and a mid-length gas system.

Centurion M-LOK rail systems are featured on Colt EPR rifles as well.

The MLOK C4 rail system is based off the Centurion CMR quad rail version. It is a lightweight, rugged, 2-piece free float rail that, when installed, provides a continuous 12 O'clock rail and MLOK slots for the 3,6, and 9 O'clock positions. The C4 system uniquely features the use of a standard mil-spec "toothed" barrel nut, which makes for an easier install and less hardware.  So:  lightweight, universal, easy to install, reuse of existing hardware. This design allows the installation of the rail on an upper assembly without removing the front sight post or permanently attached muzzle devices. 

Features and Specifications

• Sharp looking M-LOK with an FSB cut-out
• Mid-length gas system design
• Lightweight:  8.9 ounces with screws (without barrel nut)
• Re-uses existing milspec barrel nut
• 6061-T6 aluminum with Type 3 anodized black surface
• Engraved T-marks on top rail
• 1913 - Picatinny top rail
• M-LOK rails at 3,6 and 9 O'Clock
• Length:  9.25" top, 11.50" on bottom, 10.625" on sides
• Height:  2.38"
• Inside Diameter:  1.37"
• Grade 8 bolts with phosphate finish
• Engraved slick branding, no white etching
• Made in USA

Manufacturer's Part Number 0819MC

Barrel nut is not included, but is standard milspec.  If you need one, Charlie's has the milspec barrel nut here

Note:  Some front sight bases (FSB) may require minor modification to properly fit, by filing down the longer sling ear attachments, to assure they do not touch the handguard

photos courtesy of Centurion Arms and Stickman