|An amateur artist with a lot to learn.|
Pneumatic rifles are still allowed under this ruling, however the power of airguns are of course limited. Plated armor still plays a large role when fighting, and the air-gun armed soldiers would be better suited for fighting unarmored warriors.
The soldier depicted carries an air rifle connected to a compressed air tank carried on their back. Other weaponry includes a shortsword, dagger, pick, or any other one-handed armament and a buckler. With smaller air tanks or simply keeping their compressed air in small reservoirs, an airgun rifleman can carry a pavise shield for sieges or defensive battles.
Complimenting crossbowmen and archer units, an airgun rifleman would be a sharpshooter with the ability to operate their weapon while prone.