Coilguns

 

4-barreled heavy coilgun

Coilguns are projectile weapons that resemble both autoguns and bolters. Instead of chemical propellants, they use gravimetric coils to projectiles at astounding speeds. These grav coils have been developed from heretical Tau tech fused with lostech lore, then assembled in the tech-pits of Argoth.

In size they range from personal sidearms and automatic rifles that fire 5mm solid-core round, via Astartes weapon with explosive warhead, to starship batteries. Compared to lesser weapons, the coilgun has somewhat better range, accuracy and penetration, all due to its high velocity. In the case of Astartes weapons, it's got another advantage: increased ammo capacity, 2-3 times that of the most common bolter patterns.