There is no bullet travel time in FFoW (not including projectiles like tank shells, GL, etc).
See
this thread for more info. Look for the quote from Rex.
One thing that can make it more visually confusing is the tracer rounds you see actually fly out to to target *after* the hit or miss has already been calculated and damage has already been done.
Test this for yourself. Get someone to shoot a short burst at a player from range. What you will see is a spurt of blood which indicates the hit has landed, *then* the tracer round shoots out and connects with the target.
If you make the mistake of trying to lead your moving target so that the tracer rounds are visually connecting it you are just missing horribly. Ignore the tracers and try to put the crosshairs exactly on your target. The only other leading/trailing you need to worry about is to account for network latency.
Here is a
video I made when I was testing this stuff out for myself.
Hope this helps. I can say that after playing the beta for a while now I am much much more competent when it comes to hitting my targets than I was when I first started. It's a feel thing.