|Bullet Weight||55 Grain|
|Bullet Type||Full Metal Jacket (FMJ)|
|Ammo Caliber||.223 Remington|
|Muzzle Velocity (fps)||3240|
|Muzzle Energy (ft lbs)||1282|
|Cost Per Round||70.0¢ per round|
The twist rate on a .223 Rem out of a bolt action rifle is 1:12 and is between 1:7 and 1:9 out of most semi-automatic rifles, depending on the make and model. The 1:7 twist rate is extremely tight and fast. It was designed to improve accuracy of the 5.56 NATO penetrator ammunition that weighs 62 grains. The AR-15 with a 1:8 or 1:9 should be sufficient for accuracy with these 55 grain rounds.