I hardly use the spread weapons. I feel like 15m range is too short for 2H. Also very little real opportunity to hit multiple opponents. 20m seems a bit better, and still shorter than projectile weapons. I wouldn't mind if damage was reduced based on distance, maybe it is already? Like 10m full/15 80%/20 60%. Increase base damage to adjust for this.
Also, seems melta gun should maybe have a bit more armor penetration? It's same a plasma at 25 maybe 35 is better for it? Or is it intended to be a type of plasma shotgun?
I can't tell if armor penetration on weapons is a percentage or absolute adjustment. A lot of table top games use adjustment to make calcs simpler. Melta vs 60% armor, does it leave 35% or 45%?
Anyway just some thoughts