K10/22-T is beautiful. Thanks everybody.
You want a stopper - a .22 is not a stopper. It's killed plenty of folks, but it won't stop them from doing you serious bodily harm before they expire, unless you get very lucky indeed.
Also, you AIM a .22 rifle, you POINT a shotgun. Putting a lot of lead through a .22 rifle is good general firearms practice, but it will not teach you how to handle a shotgun.