77 Grain 223 and 5.56 ammo is mostly used for shooting competitions like 3 gun and 2 gun. The reason why is that the heavier and longer projectile stabilizes better for greater accuracy. Here at True Shot we carry a selection of 77 grain 223 and 556 ammo from PMC and Sellior & Bellot. Most of our 77 grain ammo is loaded with a Sierra Match King bullet. Grab a box today and give it a try. Just looking for plinking ammo check out our selection of 55 grain and 62 grain 223 Rem and 5.56 Nato ammo.