Naval Armament of the Kentucky Free State
The KFS River Patrol operates a number of Patrol Craft along the Mississippi and other major rivers. These vessels are usually armed with the same types of weaponry issued to the KFS Infantry. However there is one “Riverine” weapon that may be encountered: the 81mm mortar with “piggyback” Heavy Machine Gun.
This combination dates back to the Vietnam-era “Brown Water Navy” and was originally developed by the US Coastguard as a triple use system: machine gun, illumination system, and short range naval “gun.”
The 81mm does not operate like conventional mortars, in which the falling projectile’s primer stikes the fixed firing pin at the base of the mortar tube. Instead, this is a unique lanyard-firing weapon, in which the projectile is still loaded into the muzzle, but the gunner can “fire at will” by the use of the lanyard. The weapon had been tested in the 1950s and discarded when the US Navy lost interest in the system. It was resurrected during the Vietnam war.
The KFS has found it to be a convenient and cheap weapon and is beginning to issue it to the smaller Army fortifications – and to its colonies, the ‘Agrovilles’
see this link for real-world details