The first design is many recent rifle designs combined. Its designers say that it takes the best parts of each and puts them into a light, modular rifle. Some features from the Armalite AR-18, the FN SCAR, the Heckler & Koch G36/XM8, the M16/AR-15, and the M16 can be seen clearly. The cyclic rate of fire is around 650–700 rounds per minute. The ACR can easily swap caliber by changing the bolt head, magazine and barrel.