Add the following text to rule Weapons.

A soldier may as a daily action, if they are not participating in a Skirmish, remove one of eir weapons and set eir Affinity to 0. The removed weapon is no longer subtracted from the availability amount of the weapon.

Create a new rule ‘Weapon Affinity’

There exists a non-negative statistic called “Affinity” which is tracked in the GNDT. As a weekly action, a soldier may train their weapon by rolling 1DICE2 and subtracting 1 from the dice roll, and adding the difference to their Affinity. New soldiers by default have an affinity of 0.

The basic idea behind this is that Soldiers practice using both weapons available to their maximum advantage. Or their single weapon. When this changes, they need to re-learn how to use their weapons in creative and more effective ways. Since it takes such a while to get significant damage ratings, there should be plenty of time for someone else to propose an affinity limit and boost the weapons training while they’re at it.