Many mods, like TerraFirmaCraft, inflate damage and HP numbers. So, for compatibility reasons as well as just being able to customize NTM better, I'd suggest a config option for damage multipliers or at least one universal damage multiplier.

Are there mods other than TFC that do this?

I'm not sure what the point of inflating HP numbers is when you end up buffing weapons to compensate anyway, but that sounds like something I could do once the next gun overhaul is due.