The concept of having a spare magazine already attached on the rifle itself ready to replace an empty one is not new. But it is a nice concept and we wonder why other weapon designers do not incorporate it in most guns, perhaps due to ergonomics. For F.A.B. Defense, having the spare magazine in the buttstock should do the job and this is seen in their GL-MAG M4 Survival Buttstock and the new GL-Core M Adjustable Stock with their magazine carriers.

According to F.A.B Defense, the GL-Core M Adjustable Stock is designed for use by law enforcement officers. Police officers are usually equipped with sidearms rather than rifles and their spare magazines on their duty belts are for their sidearms. But when equipped with a rifle that they retrieve from their vehicle, such as an M4, they don’t have spare magazines on their belts. The GL-Core M with the magazine carrier should provide that spare magazine when it is needed.

The stock features an anti-rattle firmly holding the stock with the tube so there won’t be that annoying rattle.  As for the butt-pad, it is made out of a high-quality rubber to prevent it from slipping while shooting and enhancing the grip on the shooter's shoulder.

F.A.B. Defense list of advantages of the GL-Core M as the following:

• 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

It is now available at F.A.B. Defense USA website or via their dealer network. Price is US$122.00 (US$199 with the cheek riser option) and colour options are Black, OD Green, and FDE.