I must have missed your second point (or you edited it in). The maximum range for the P90 is 3700 in-game units (308ft) compared with 4000 units (333ft), so you cannot!
That said, very few places in any official CS map have ranges that long. One would be on Train from Terrorist spawn to "Ivy" @ 3900 units (325ft).
That said, very few places in any official CS map have ranges that long. One would be on Train from Terrorist spawn to "Ivy" @ 3900 units (325ft).