I mean I'd say it's because of ammo, but you could use boss/crit dmg or something... I don't think attack speed or ammo is the core issue with HG. Ammo doesn't matter 99% of the time, and stacking attack speed is bad for DPS anyways, even in spire, boss is just better. I wouldn't want them to just buff our ammo consumtion and assume it's a buff, since most gunners do not run out. I would consider buffing ammo consumtion more of a QoL, since imo it doesn't really need to exist, but you will not notice it 99% of the time you play HG. For ammo to run out you need extremely high uptime for a very long time, and also attack speed, and usually holy symbol. Of course if you have a ton of attack speed you will run out, but that's bad anyways.