Musket physical damage?
 

Anyone knows whether muskets and machine guns are effected by the Pyhsical Attack stat? I'm asking because the manual states they do not, while there are in game green muskets/machine guns that have the +Physical Attack bonus. I'm assuming item bonuses can't be useless because I haven't seen one yet (e.g. staff with +STR)

And if I got this right, weapons effected by increasing STR : Swords, blunts, axes, staves, electric shockers and bows
And those that don't : Buzzsaws, crossbows, muskets, pistols and machine guns
Is that correct?

you are correct, also flamethrowers aren't affected by str either.

I think one way to improve the damage per second on the latter categories, is with passives (ie alchemy's poison skill), more agi for aspd, and more perception for crit procs.