shot from a 22 LR handgun and the ones that do, do not penetrate deeply enough. The 22 LR rifles are a different story—if this is the only longgun that you have, then it is an acceptable choice if you cannot find a larger rifle. Please recall that if you are in a position to fire a firearm at an attacker, they are usually in a position where they can fire a weapon at you. If you are going to expose yourself to danger, try to reduce that danger by hitting it as hard as you can, the first time that you pull the trigger.
If a 22 LR handgun (with 3.4” barrel) is what you have available, I recommend using JHP ammunition that exhibits very moderate expansion such as the Winchester 40gr Super-X Power-Point (X22LRPP.) Second in preference is the Aguila 60gr Sniper Subsonic round nose because of its exaggerated length over diameter ratio and its usually unstable travel out of the rifling twists found in most handgun barrels. This promotes tumbling early inside of the target and is acceptable as long as practical accuracy is maintained.
If a 22 LR rifle is what you have available, you have many more choices available to you in terms of ammunition with satisfactory terminal performance. One metric of success is to find ammunition that meets the FBI criteria, or more accurately, gets full ‘points’ for penetration depth in 10% ballistic gelatin by penetrating to 12.0” or deeper. Expansion of course is important too so the best course of action is to test your ammunition, out of your gun, in ballistic gelatin or ’wetpack’ and look for the bullets that exhibit only moderate expansion. Here is how to do so: