Thanks guys!!
I agree on the 330's Tom, but we only have 6 of them to use, so we have to use snares eventually.
Our drowning wires run about 12 feet from shore, but it's still only waist deep at the end of them, and I would think that a beaver could get his head above water.
I didn't think about the current, the river moves pretty quickly, and because of that the bottom is all rock and gravel, which makes driving a stake almost impossible, so we are using sacks filled with rocks for anchors. Like you said RdFx, we'll try the weight idea!!
It's our first attempt at drowning beaver, so I guess we'll have to wait and see what happens. Do you think the current alone can tire the beaver out eventually?