The military is quite active due to border disputes with neighboring kingdoms, wandering predators, and attacks from feral Savages. Because of this, all Mice and Rats are encouraged to spend a season or two in active duty "For Queen and Country." Nationalism aside, the largest draw to the Military is the Royal Airnavy.
Though blades are still used and muskets are not uncommon, the primary weapon on the battlefield these days are compressed steam guns. These weapons propel a bullet by expending a single-use compressed steam canister. These tend to be single shot, or semi-automatic weapons, and though automatic weapons are available, science has not yet made them portable.