Equipment and Weapons

so example:

if i had 300 str and i bought the "Cross' Sniper Rifle" (thats gives 10accuracy/110damage)

and

"Phosphorus Bullet Coating" (that gives 90power)

i would have 300+110+90=500str??

i dont get that and what does the accuracy have to do with anything?

You think we are going to tell everybody the formula?