The .22 Short was developed back in 1857 for Smith & Wesson revolver. Created for the metallic cartridge with a 29-30 grain bullet, pushed by 4 grains of black powder. This was mainly developed for self-defense, nowadays this cartridge has little penetration and knockdown power. So how low in caliber should one go before your personal defense firearm is too light? Youtuber mark3smle did some ballistic gelatin test with this .22 Short. Overall the .22 penetrated 4 inches through a pair of pants into the gelatin. mark3smle goes onto comparing a knife penetration could do the job as well. Theres...