Scorpion Ammo 5.56 NATO 55gr Rifle Ammunition

Scorpion Ammo lists this cartridge as 5.56x45mm with a 55 grain bullet. That is the chambering marked on AR-15 pattern rifles and on other barrels cut for 5.56 NATO, and 55 grain is the classic bullet weight for the cartridge.

Grain weight matters more than most shooters expect. A rifle zeroed with 55 grain ammunition will hold that zero with another 55 grain load far more closely than it will with a heavier bullet, so matching weight is the simple way to keep a known zero honest. This load keeps that weight.