The use of the newer ultra high velocity 33 gr rounds should do adequately in this cartridge in a self defense situation. The 22LR Stingers and other HV Long Rifle rounds produce wound channels and penetration much like 38 Spl 148 gr wadcutter and 158 gr semi-wadcutter loads. The 22 WMR should do as well though the higher velocity may decrease penetration by over expanding. Ultra high velocity solids may be a better choice than the HPs in this instance though that is total supposition based on reading on the effect of the 22LR. The standard hollow points in the 22 WMR are only occasional expanders in handguns even though their velocity is relatively high. Fr personal protection it does beat a Bic ball point by a fair margin in my opinion.