Originally Posted by CR0M
is there a big difference from 400 - 427 fps?
In many areas, the difference between CQB FPS (350fps) and outdoor FPS (400fps) is 50 FPS. Those are the velocities at which the risk of injury is sufficiently reduced to be considered 'acceptable' for the typical engagement distances of those environments.
Those velocities are not entirely arbitrary: they were found through trial and error. In the days I started playing, I did see 420 FPS guns in CQB, and yes, people got hurt.
Would going from 400 to 427 fps outdoors make a huge difference? At range, it would hit a bit harder but not much. Mid-range it would sting a lot more. But if someone happened to hit you at the minimum engagement distance there's a good chance you'd have blood or even have to dig out the BB from under your skin: probably not something you want and definitely not what most people, who came out for a fun day with friends, want to have to deal with.