During the course of World War I, as with the production of the P-14 rifle, Britain turned to the United States to help with ammunition production. This call was answered by Dupont and their IMR 16 single based nitrocellulose powder. IMR 16 closely duplicated the performance of the Cordite loading, but had the advantage of burning cooler and as the ballistic characteristics was near identical to the Cordite loaded round, it kept the Mark VII classification, but with the addition of a "Z" (Mk VIIZ) to denote the propellant change. The nitrocellulose powder also offered the added benefits of not having to alter existing or future rifles’ sights and because of its cooler burning, prolonged the normal service life of the Enfield barrel. After the war, this powder was offered for public consumption as IMR 3031.