Belmont Ammunition was first established in New Zealand in 1967. Since then, Belmont has grown their Whanganui factory and transformed into the country's only dedicated ammunition manufacturer, producing millions of rounds each year for sporting, military, and law enforcement purposes in both the domestic and international markets.

Belmont's 303 British ammunition was manufactured using surplus Canadian military ammunition produced by Defence Industries Limited (DIL). It comes loaded by Belmont with a 150-grain pointed soft point projectile, fresh powder, and uses boxer primers. Each case is headstampted with "DI Z 1943" indicating that it was originally manufactured by Defence Industries in 1943.