For the old muskrat in the water a drowning set it doens't take much but a beaver a lot big like stated in the post before mine check all your laws on large body grip traps in missouri you can't set a 3 30 above the water or withen 200 or so yards of any kind of house 3 30 and 2 20 work good for beaver 1 10 work good on rats and 3 0r 4 coilsprings work good for beaver on drowning sets also