Nothing a'tall wrong with carrying the very lightweight 351PD in 22 magnum if you will use some of the special self-defense ammo made for the short-barrel revolvers, such as Hornady 45 grain Critical Defense JHP or Speer Gold Dot 40 grain JHP.
If your lifestyle is such that you would not normally expect to encounter danger in your everyday comings and goings, then 7 rounds of 22 magnum should be more than sufficient to address any self-defense issue that reasonably could arise.
Sure, you could carry bigger, heavier, and badder boolits and the revolvers to shoot them, but the great thing about the Airweight J-Frames is that they are literally "pocket pistols," as in "front pocket" and weigh not much more than your cell phone. I carry mine in a Snubbyfan leather pocket holster, and for me, the 351PD is the ultimate EDC for someone like me who is a civilian, leads a calm lifestyle, and can put all seven 22 mag rounds on a paper plate at 3 and 5 yards in less time than you can unload your 3913 onto the same target. The holes made by my JHP rounds are plenty big to do the job, and the 22 mag rounds are loud, with muzzle flash, that do their jobs as well.
I have read on this Forum that a 22 round (not magnum, which will work even better) to the midsection will double over an attacker immediately, according to an ER surgeon.
YMMV, but I'm a big fan of 22 magnum, having seen the results in ballistic gel, with penetration similar to that of 38 Special and muzzle velocities around 1,000fps.
It's all in what you will carry, every day, and I haven't found a more comfortable revolver than this one.
