Tony has that one pegged.Best time to make your mound and lure it, would be just before dusk--or just as it gets light out in the morning.
I have trapped several(instant beaver over the years),I had to get out of the way so they could get into my trap.
While this will work at times with a gun,like tony has said--you may wait a long time.
While expensive, large live traps will work, just not as easily or quickly as a 330.
Tom