The Dead Foot Arms Modified Cycle System is a retro fit kit that allows a standard AR-15 platform to transform into a folding stock rifle. Utilizing proprietary dual spring technology, our Modified Cycle System reduces bolt bounce and reduces the overall length of a rifle with a 16 inch barrel to 26.5 inches when the stock is folded. The built in folding stock adapter provides positive retention when the stock is folded, and with a quick swing of the butt stock the adapter ensures a rock-solid lock up in the deployed position. Our system includes: a modified bolt carrier group, recoil springs, and folding stock adaptor kit. The end user can use their current butt stock or any butt stock that will attach to a standard AR-15. The Modified Cycle System attaches only to the lower receiver, allowing the use of any upper receiver of any caliber and any barrel length combination. THE DEAD FOOT ARMS MODIFIED CYCLE SYSTEM ALLOWS THE END USER TO MAINTAIN THEIR CURRENT ZERO AND SIGHT PICTURE, AND SUPPORTS FULL AND SEMI-AUTOMATIC FIRE WHEN THE RIFLE IS FOLDED.