They don’t sink right away when you shoot them in the head with a .22 Mag or .17 hmr.......but will eventually. Those calibers will penetrate the skull and death will be instant. A .22LR will work to knock them out but it doesn’t usually penetrate the skull. I don’t rush too much to retrieve them but I don’t waste any time either. You usually have a few minutes anyway.
Do you guys use a fishing rod with a heavy treble to retrieve them?
I have used that before
A small 12 ft boat worked good when I was floating down a river always tried to get to them a fast as possible after shooting them so they didnt sink
I used a 12 foot Jon boat with electric motor on the river or creeks floating down stream in evenings after making beaver sets , i had a heavy duty net tied to boat made from a bicycle rim when they are rolling in the water sometimes after the shot no way i was gonna grab them by hand seconds count once they are in net you got him. The wife used to net them almost got hauled overboard a few times lots of squeaking going on .
I use one of those paint roller handles that extends to 16’. Removed paint roller and bent the head like a hook. Light and you can reach those ones in deep water. Have used a number of caliber rifles over the years and settled on the .22 lr. It all comes to bullet placement. And have no problems with quick and instant kills the norm. And bullet does go thru the skull.