A round of ammunition for firing from a gun having a rifled barrel, especially a small arms weapon. The projectile (1) forming a part of the round is of steel or other material having a Vickers Hardness value not less than 550, and has a coating (13) of copper or copper alloy. The projectile has a forward body portion (9) which has a diameter similar to that of the lands of the rifling, and a rearward body portion (3) having a diameter which is similar to the diameter defined by the roots of the rifling grooves. The coating (13) is of a thickness not less than the depth of the said rifling grooves, so that the rifling engraves the coating but does not significantly engrave the underlying steel or other hard material. The advantages associated with a hard projectile material are thus obtained without substantially increasing barrel wear.