Just an observation: if every capable citizen, male and female, is armed, then there's no "mobilization" required. It's true that it would be impossible to go around invading other countries without assembling an army, though...
Rifles were by far the least of our worries back then -- but even so, you need to have everybody armed with the same rifles in order to be able to efficiently supply your troops. Gosh ... rules and regulations regarding what weapons to bear?
We had almost no artillery, and almost no ammunition to fire from the guns we did have. We had no airplanes. We had no machine guns. We had to borrow or buy all of those from the British and French. We also had to rely on British transports to get our guys over to Europe.