Introduced in 1929, the 7.5×54mm French MAS is another round that can pass for the 308 Winchester to the eye of most novices. The cases are very similar. Diameter of the French round is slightly larger at the base and slightly smaller at the shoulder. Shoulder angle is identical and neck length is almost the same. The case is 3-mm (0.120-inch) longer and cartridge overall length is similarly longer. The French round works at significantly lower-pressure, 55,000 versus 62,000 for the 308 Winchester (7.62 NATO). The difference in usable capacity offsets the difference in pressure and the two are ballistically indistinguishable when loaded with the same bullets at full specification-pressure using the best propellants. The U. S. Military had very good reasons for basing its replacement on the 30-06 case but it certainly could have just as well sized the 7.5 Mas, or the 7.65×53 Mauser to use 0.308-inch bullets and achieved indistinguishable ballistics. The one advantage the 308 has is the slightly shorter overall length, which might matter in terms of ammunition packaging for shipment, which matters in wartime. This is a long way around the block to say: the 7.5×54 will do anything the 308 Winchester will do. The only issue is, groove diameter is supposed to be 0.309-inch. Slug your barrel carefully. Depending upon what you discover and what will freely fit in the chamber you might find better accuracy by using 0.311-inch bullets.