FAB Defense GL CORE MAG - M4 Survival Buttstock w/ Built-in Mag Carrier Black. 56x45 (.223 Rem) AR15/M16/M4 and FAB Defense Ultimag Magazines. Whether its for accuracy or multiple target engagements you can depend on your last ten chances with the FAB Defense "Survival" AR15 Butt-stock w/Built-in 10r Magazine Carrier. The CORE M AR15 Stock has a unique Anti-Rattle mechanism that holds the stock firmly in place on your AR15 tube eliminating any unnecessary rattle furthermore the butt-pad in made out of a high-quality rubber to prevent it from slipping while shooting and enhancing the grip on the shooter's shoulder. The stock will fit both MIL-SPEC and Commercial tubes. Specifications for FAB Defense GL CORE MAG CP - M4 Survival Buttstock w/ Built-in Mag Carrier: Manufacturer: FAB Defense Gun Model: M16 M4 AR-15 Gun Type: Rifle Condition: New Buffer Tube Size: Commercial or MIL-Spec Features of FAB Defense GL CORE MAG CP - M4 Survival Buttstock w/ Built-in Mag Carrier Sleek design with no protruding parts will not get caught on gear or webbing Keeps all of the characteristics of the M4 buttstock while incorporating a State of the Art magazine carrier Positioned close by for convenient mag change providing you with the edge you need Incorporates a quick release button for swift clip change Does not interfere or change buttstock to shoulder positioning Integrated ambidextrous quick detach rear sling swivel connectors Fits on both Mil-Spec and commercial tubes Made with fiberglass reinforced polymer composite Package Contents: FAB Defense GL CORE MAG CP - M4 Survival Buttstock w/ Built-in Mag Carrier Cheek piece What firearm models does the manufacturer say FAB Defense GL CORE MAG CP - M4 Survival Buttstock w/ Built-in Mag Carrier is compatible with? The manufacturer suggests that FAB Defense GL CORE MAG CP - M4 Survival Buttstock w/ Built-in Mag Carrier is compatible with AR-15 M4 M16FAB Defense fx-glcoremagb: GL CORE MAG - M4 Survival Buttstock w/ Built-in Mag Carrier Black