I guess my point is that all things being equal .380 have less kick than other cartridge and .380 is about the bottom of the range for effective defensive rounds.
I think you can shoot any round accurately, you may not like practicing with it or your follow up shots might take a second longer with some guns than others but you can train yourself with almost any gun. Heck I fire a 3" barrel .460 bear gun pretty accurately but it would take a bear coming at me to want to fire that gun. The .460 10" barrel on the other hand is not much worse than my 1911 or even my glock 27 (its just frikking heavy).
If you mean “the largest round she is comfortable with” then I would say that anything less than a .380 and you had better be a pretty good shot if you want to stop anyone.
Then they should buy one of the .380s that are made of metal rather than polymer. You can’t do anything about the flip but you can reduce recoil. A .380 has very little to begin with. (full disclosure, my carry pistol is a glock 27, it took some getting used to).
That and they are so dirty that they get gunked up real fast.
AKA “don’t just leave your gun lying around”
I’m not saying I would enjoy getting shot with a 22lr but there are a lot of risks I would take against someone firing a 22lr that I wouldn’t take with someone carrying a .380 or bigger.
IMO, the glock 27 is almost made for carrying on your waist with the short grip. I have several conversion barrels for it and I have had great luck with a lone wolf ported 23 barrel in the 27. The extra length gives it more firepower and reduces and the porting reduces recoil and the gun doesn’t flip nearly as much. It adds a little weight but it does not affect the draw or concealability in an inside waistband holster. Its basically a 23 with a 27’s grip. YMMV.
And we also compared defensive gun use to gun injuries. But yeah, some people should carry guns just like some people shouldn’t drive.