Proponents assert that the Grendel is a good "middle ground" between the 5.56×45mm NATO and the 7.62×51mm NATO. It retains greater terminal energy at extended ranges than either of these cartridges due to its higher ballistic coefficient (BC). For example, the 123 gr (8.0 g) 6.5 mm Grendel bullet has more kinetic energy and better body armor penetration at 1,000 m (1,100 yd) than the larger and heavier 147 gr (9.5 g) bullet of the M80 7.62mm NATO round. In order to obtain ballistics that are superior to the 7.62×51mm cartridge, a weapon with a longer barrel and firing a heavier bullet is necessary. To achieve the same results from shorter length barrels, even heavier bullets are needed.