Afew years ago my uncle was hired by a golf course to remove a beaver infestation. I went to visit him while on leave that year and he took me along on this culling expedition
. When I was stationed up at FT. Wainwright back in the late 80's I had killed afew of them, so I guess he thought I knew what I was doing
.
Well we got to the golf course and I was shocked at what the little beasts had done to the place. They had absolutely trashed the greens!
They had mowed down trees, eaten the landscaped shrubs, and flooded most of the water features. It was a sight to see!
My uncle had been shooting these things with every type of gun he had, he had killed afew, but most of the time they would submerge after being shot and float up later. Needless to say the golfers raised hell about that! What we determined to be the problem of that was he had relied on a 25-06 for most of his shooting. While plenty of gun to kill one, because of the flat skull most of the time the bullet would crack the skull but not penetrate. That was a bad way to go for the beavers!
I witnessed it with my own eyes, I watched him shoot a big one and even saw the bone exposed where the scalp had been blown away, it submerged and was gone. Not good...
His thinking was that a bigger heavier bullet might richocet and hit something; I agreed. He thought the fast light bullet was more likely to explode when it hit the water; I agreed. The problem was unless he hit it in the side, or back, of the head they would more times than not get away. He had a Savage 22 Mag, we tried that, it worked much better. The best weapon we used was not a gun at all, it was our compound bows with a bow fishing setup. We switched the fish head with a Broad Head and we very successful! The Broad head really did the trick and we would just reel the beaver in! With this setup we could shoot right for the body under water and in a few seconds pull the critter in! We got nine in two evenings and no worries about richocet's.
The end of the story was a sad one, the beaver were migrating in from a creek that the owner had diverted for his water hazards. The more my dear uncle would shot, more would migrate in to take their place! In the end, about a year later, the owner tried to turn it into a commercial catfish farm! That went bust too, the little monsters eventually flooded that out to and his fish escaped!
The golf course / catfish farm is now a beatifully manicured cattle farm!
I wouldn't recommend a 223, or light weight varmint gun. The chances of wounding them is to high for my conscience. A 30-30 would probably do the job reliably, but the Bow fishing setup worked very well.
Good luck, and keep us posted on your results.