Lee,the largest percentage of my beaver are taking in castor mounds.I usually half submerge my 330,by bending the trigger--it looks like a rounded m.When I half submerge the 330 in front of my castor mound,the trigger is under the water.This provides a wide open window for the beaver,all he sees when looking throught the trap --is the mound--and a clear path to it--no obstructions what so ever.
Also by placing the trigger on the bottom,you avoid fur damage.When trigger placement is on the top,at times the trigger can actually be driven into the beavers back--causing damaged fur.While this is kind of a freak happening--it does happen.One beaver damaged in this way,will quickly cause you to change your trigger placement---it did for me.
Tom