I have all the guns you state you have and they are currently my main carry guns. I have or have had some of the guns you are considering.
S&W Shield Still no size improvement over a Glock 26 right?
I disagree. The shield (and all the other guns in that size range) is/(are) notably thinner and carry differently. This size of gun is about as small as I would care for in a primary carry gun. Anything smaller and you are giving up too much in performance IMHO. Between the PPS, Shield, Glock 43, XDS, P9, etc I would not base my choice on de minimis size differences. I would base it on what else those guns bring to the table.
If you don't find yourself having issues with the G26 related to the width then it may not be worth going down this road.
Kahr 380 or 9
Kahr's seem the most promising, with the two tone scheme they seem durable, and the 380 or the 9 are both quite small, from the pictures I see. Comments on either? 380 compared to the LCP? 9 compared to a Glock 43 or Glock 26?
Which Kahr are you considering, there's the K9, MK9, P9/CW 9, PM/CM ?
The P9/CW 9 are roughly the size of the shield, PPS etc. The K9 is a great gun but is slightly thicker in the grip and of course heavier.
The PM and CM 9s are smaller and are IMHO about as small as you can get in a 9x19 and retain any kind of practicality. Sure a R9 is smaller (and way more expensive) but IMO it gives up too much to be that small and the size. I would not choose to carry an R9 over a PM and that has nothing to do with money.
The Kahr 380s are IMO nicer guns than the LCP but if I had an LCP that I was happy with I wouldn't go trade. If one is unhappy with the LCP in general I don't see them loving the Kahr. Its nicer in some respects but for the intended use of such guns there isn't much difference in my experience. One would get more out of spending the money on ammo and training than getting the new gun. The finish on all the kahrs I have experience with is better than that on my LCP. The LCP shows a lot of wear on the slide. However, it does not affect function in anyway and it is a concealed that cost < $250 new so I don't really care. I likely would have bought a stainless steel slide knowing what I know now if they would have been offered when I bought my LCP. However, I wouldn't go buy a new one to replace the one I have over finish wear from honest use.
I have or have had various snub nose revolvers. I prefer small single stack 9mms. I prefer the CM9 to the J frame and LCR. More ammo, I shoot it better (that admittedly is a me issue but I do). Everyone should probably own a snub just to have one but I almost never choose to carry one these days.
In my opinion it is almost always possible to carry a G26 (and the same is true of a G19) with proper carry position, hoslter etc. I carry a 17 most of the time including with tighter jeans and a t shirt. I think that either something like the size of the PPS/Shield/etc offers a good in between to what you have as does a PM/CM9.
You need to look at when you are not able/willing to carry the G26 and why and how those other sized guns fit that paradigm. I think that both the CM/PM9 and the pps/shield/etc offer performance over the LCP in terms of cartridge but they are just easier guns to shoot well and manipulate too IMHO. The G42 is a much better shooter than the LCP as is something like a colt mustang. When you get into comparing bigger 380s to smaller 9x19s I think the issue becomes how well can you shoot them. I'd take a G42 I could shoot well over a CM9 or 357 snub that I struggled with.
I suggest you consider what real gap you are looking to fill. Go handle some those guns and compare side by side, borrow something in that size range if you can and experiment with carry shooting etc. Try to get some trigger time on some of them.
