PROJ EXTRA RAND

defineprojectile <tilenum> PROJ_EXTRA_RAND <extra rand>

PROJ_EXTRA_RAND is a random value added to a projectile damage.

By default it is 5, meaning that a SHOTGUN projectile (which damage is defined as 10 in USER.CON) will make cause a damage of 10 to 15.

Setting it to zero should cause the projectile to inflict the precise damage defined by PROJ_EXTRA.