.22 accuracy
If you're talking about accuracy:
About 10 years ago I Bench rested a my Ruger MkII with a 5-1/2" Bull Barrel on sandbags at the 100 yard range with a 7x scope, and test 16 different types and brands of .22LR ammo. I don't remember all the figures but I remember the best and the worst. The worst was any of the hypervelocity rounds, most averaged 6"-8" groups at 100yrds, the worst thought were the Yellow Jackets, they grouped about 14" @100yrd. The best, of the ones I tried at that time, were the expensive Eley Tenex rounds(though Lapua might be better now), they gave groups averaging less than 2" with the best 5-shot group at just under 1". It's interesting to note however that one of the least expensive, some Winchester .22LR rounds they sold at the range for about $3, were almost as good as the expensive stuff, giving groups about 2-1/2". None of the stuff I tried from CCI worked out very well, falling about the middle of the pack.
If you are talking about a .22 round out of a 2.4" barrel for self defense then:
It really doesn't matter, what ever you use will be fine, they will all poke a painful hole in the guy and they all can be deadly if they land in the right spot. Any of them will work, even the .22 short might be a good idea, it might give the effect of having a slightly longer barrel for the bullet to accelerate in.