I hunted frogs with a BB gun. It is a Daisy with a rifled barrel that handles BBs and .177 pellets. I still have it.
I prefered squirrel and crayfish to frog legs. I never thought to use a .22 rifle to hunt frogs, and I bet my Dad would have nixed it, with concerns of ricochet, we weren't typically allowed to shoot rifles around water, as I think that was what he was worried with.
That was a long time ago. Used to sneak up on the frogs on the beach, and put a BB just behind the head, and centered in the back. I worked at a resort, and collected bait, and shot frogs to sell, $1.50 for eight frogs, or 16 legs, if I am remembering right. They never even flinched. Some people bought them for bait, some people fried the legs.
Was either three or four pumps of the handle. The gun would take ten, but, a BB got weird with that much power on it. Pellets worked well at higher velocitys, but, were more money than BBs, so, us kids never had them.
I got two pennies each for night crawlers, one penny for red worms, 2 pennies for crickets, and a nickle for crayfish. I spent the most time digging worms, and made the most money on crickets and crayfish.
I had a ton of fun as a kid, now that I stop to think about it.
Best,
Ted