IMHO not a good idea, unless for protection from small/medium sized animals. If however you really need to have a pistol, but are disqualified from carrying, I would say the below is your best bet. Not small, nor concealable by any means, is only a single shot, but does have just about the same muzzle energy as a .22 short.
https://www.airgunsofarizona.com/usedguns.html/quackenbush-pistol-.25-50-ft/lbs-w/scope-used/
Just carry a black powder derringer or even a black powder revolver. Downside is you cannot carry them concealed. They are not considered firearms, but they ARE still considered deadly weapons and thus cannot be concealed.