Even if the velocities are the same, the .22 LR (40gr bullet) is going to have ~38% more mass than the .22 S (29gr bullet) and, at the same velocity, more impact energy, better sectional density (weight to diameter ratio). The longer .22 LR bullet tends to "flip" after penetration in ballistic gel and stops traveling base first. (Gives me confidence that the round will do internal damage to an attacking ballistic gel block.)only difference between the .22 Short and .22 LR is bullet weight
To me the NAA is the modern equivalent of the "VeloDog", revolvers carried by turn-of-the-centurt cyclists for protection against free-roaming dogs, and if I owned one, it would be .22 magnum because most .22 magnum ammo is more reliable (fewer duds than common .22 LR ammo). The short NAA barrel does not take full advantage of the power of the .22 magnum over the .22 LR.