I think it stands to reason that a country will not arm its defense forces with junk. In most cases, a nation's service rifle, whether Carcano, Arisaka, Mauser or Springfield, will be the best that can be made that will fill the need and be suitable for the country's troops. Sometimes, budgetary constraints will force keeping a rifle in service after it is no longer first rate (the Carcano or the SMLE come to mind), but that is in comparison, not an issue of quality.
Whether, in the test of war, a nation wins or loses rarely has anything to do with the quality of the service rifles used. Stories that "we won because we had the Garand" or "we won because we used a .45 pistol" are stories that neatly ignore the thousands of other factors involved in wartime and the fact that small arms really are not of much import in a modern war. Obviously, an army needs small arms, but the decision in, let's say, Afghanistan, is not going to depend on the caliber of our rifle or whether it uses gas impingement or a short stroke piston.