Kodabow manufactures crossbows patterned after the AR-15. Their bows features an M4-style adjustable stock, weaver rails and AR-15-esque pistol grip.
From the webpage for their Alpha Strike bow …
155 lb Draw Weight Lightest draw weight in the Kodabow product line. Key benefits include “easy to cock” weight and all the strength and craftsmanship of heavier weight bows. Can be upgraded to a heavier draw weight with optional extra set of limbs. Quiet and dependable. Modular core platform provides additional accessory mounting positions. * 13 3/8″ power stroke * 272 fps @ 350 gr arrow * 57.5 lbs of KE * Automatic Safety and Anti-Dry Fire System Patented Kodabow trigger system (CFT), Solid Rail Technology (SRT) with hardcoated finish, Dual Limbs with Dynamic Flex Energy Storage (DFES), Machined Riser and adjustable military style stock. Weaver style rails. Includes cocking rope and destringing aid.
Price is $874.98.
For a real AR-15 crossbow, see the PSE TAC 15.