As I said somewhere else
For Bolter / revolver-shotgun, I would invert values. I really think that it is totally stupid to see that with bolter (caliber .75 - 28mm) has twice the ammo of a revolver (caliber .45 - 11.43mm) or more than a shotgun ( 18,5mm).
In other words, revolver needs 2 - 3 times the ammo of the bolter, and shotgun twice…