The 338 ARC was designed around heavy bullets in AR-15 length actions, and this Ultramax load leans into that with a 300 grain boat tail hollow point match bullet. Three hundred grains is the weight class 338 ARC shooters pair with suppressors, where the cartridge makes quiet, heavy hitting sense out of a compact gas gun.Factory ammunition for this young cartridge remains scarce, and Ultramax is one of the few loaders producing it in volume. For shooters building out a 338 ARC upper or bolt gun, factory loads like this are the straightforward way to prove the chambering before committing to handload development.