If you fire 10 shots per second, then the time in seconds between each second is the reciprocal of 10.
shots per second = 10
delay per shot in seconds = 1 / 10 = 0.1
For RPM, you'll want to first convert it to shots per millisecond.
800 shots per minute = 800 * 60 shots per second = 48,000 shots per second = 48,000 * 1,000 shots per millisecond = 48,000,000 shots per millisecond
delay per shot in milliseconds = 1 / 48,000,000 = 0.0000000208333333333........
This number is so low that you can't viably use it as a delay in weapon states. For an accurate simulation, you would need to be running the game at 48,000+ FPS.
You'll want to either use a lower firerate or fire multiple projectiles in groups at a slower rate.
800 shots per minute = 800 / 60 shots per second = 13.33333... shots per second = 13.33333... / 1,000 shots per millisecond = 0.0133333... shots per millisecond
delay per shot in milliseconds = 1 / 0.0133333... = 75 MS
75 MS is the delay you're looking for.
