Besides what all the detractors say, the .22 rimfire has killed a lot of people in its time, and while not the first choice of most, it is as deadly as any other gun. In a SD situation, a rapid group firing of multiple shots, all put on target, is key.
Personally, I would stick with the solid point bullets, and think penetration. I wouldn't focus too much on bullet performance.
When funds allow, think about upgrading. You can still find some great deals here and there, police trade ins, that sort of thing.

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Geoff. Since 1960.