As it says on the tin. The spanking new cartridge can be for SMGs/pistols (reason being so these can fire with less recoil, and/or so the infatrymen can carry more ammo, and/or so the effective range fire requires less of guesswork etc), for carbines (for better firepower/less recoil/more ammo carried etc), for rifles (same as above, plus better suitability for self-loading rifles), MGs (both for LMGs and vehicle-mounted ones). Cartridges can be historical types , as well as non-historical - required is that cartridges can work with technology and materials of the day. Introduce new weapons if you want, or modify the existing types. For the ideas take a peek at enemy arsenals if you want.
Yes, you have the money to do it. Note - just one cartridge per country per person.
Yes, you have the money to do it. Note - just one cartridge per country per person.