I carry 24/7. Most situations involve little to absolutely no risk. Even if (when) I move, my job will occasionally put me in potentially dangerous spots. That's just the way I'm wired. I need a lot of variety in my life.

Does my work allow? Danged if I know, or care. I never asked and have never been told. I am a contractor, so no employee handbook. There ain't nobody but me to cover my back.

So, if I'm buying a new gun anyway:

There are a couple caliber extremes that I am now considering.

• As long as it is just going to sit in a loose pocket and any gun is better than no gun...Why not a tiny flat .22WMR?
• In the spring and fall, I have lately been plagued with a couple black bears. NAA used to make a Derringer with an interchangeable 45 70 government barrel. The peace of mind just might be worth a potentially broken wrist.

BTW. Bond Arms, that has been recommended by YT30, and ADC also makes a model called Back Up that comes in .45ACP. Most of those Bond Arms derringers have interchangeable barrels of several calibers. That makes the decision a bit easier.

IMHO those 45-70 derringers are not much more than a gimmick as you just don't have the barrel length to get the necessary velocity to those heavy slogs. You'll have one heck of a muzzle flash though. Not that that fireball will do you or any else any good. In a small pistol like that they 45APC is more than enough cartridge. The upside to that is that you use that round in your primary sidearm as well.

yea large caliber derringers hurt. My turd head brother in law bought a 44mag derringer and ask me to shoot it. Immediately I knew it was a mistake. Took about a week for the swelling to go down in my right thumb .

a new big caliper low capacity gun might not be the answer.
we see many cases where he who has the most capacity wins in one example the cop and criminal were carrying the same gun and driving the same car , they dance around the cars shooting at each other , the cop with the reload wins this is slightly different than a citizen shooting but maybe not that much if they are committed to getting what you have.

a 45acp is .452 a 9mm is .355 .452-.355=.097" .097/2=.0485"

the question is at what point does 0.0485 inches make a bad shot a good shot? VS when does an extra round or two make a difference?

procedure and positioning like looking for a way to pocket carry in vest , jacket , ect a concealed sub compact 9mm with a compact light it could be without the light if you don't think light is an issue.

then at the same time figuring out better ways to keep your hands free or more free like a bag to hold the product.

I always liked the idea of the keltec pm30 for a carry gun. Figure with 30 shots of .22mag - something got to give.

I have shot the FN 5.7 also - it is extremely nice and comfortable.

Carhart coats have big pockets. Carry a revolver in the pocket.

I used to carry a Glock 27 as a secondary firearm they are surprisingly easy to shoot and accurate for a handgun that size in 40 S&W it is also extremely reliable. Obviously, since it is a Glock a rigid holster is required but several companies make a "holster" that covers the trigger area with a cord that attaches inside the pocket to pull the cover off as you draw the handgun.

they are rather large almost identical in size to a Glock 17 a touch taller and a 1/4 inch less in length.

https://alabamaholster.com/product-category/pocket-holsters/
they used to make them to your shape if you ordered it, I think you sent a cardboard cut out of the shape , not sure they still do
this is how I pocket carry a LC9 my first holster cracked at about 10 years I liked it so I ordered another to replace it

Technically 31 shots. https://www.budsgunshop.com/product_info.php/products_id/64077/kel-tec+cnc+pmr-30+30+1+.22+mag+4.3 price doesnt seem too bad all things considered. It's my long list of guns I'd like to have someday.

A whole bunch of numbers and made up scenario does not apply.

I just need something in my hand to buy enough time to grab my primary.

Maybe at this point I should mention: When the SHTF,

• everything in my hands is now on the ground
• My weak hand is on this new undefined thing
• my strong hand has ripped open a little Velcro® and on primary.
• If weak hand solves the problem; end of story
• It not, well, we are back to original scenario

That .380 makes a pretty good back up gun. But it sounds like you need the little gun for primary defense with the high capacity gun for back up. Most if not nearly all self defense shootings are over in 2 shots or less.
I'd get a double stack 9mm for that strong hand pocket if that's where you are going to first.Glock 43 or 43x might work.

Check out Bond Arms derringers. Many calibers to choose from and you can buy multiple different caliber barrels that interchange so you have multiple choices.

Yup

John Wayne shot the holdup man with his derringer then he said "you should got into another line of work "

As I see it, you have a pretty decent back up.

But maybe need to be evaluating in what, and where you’re putting your primary that you feel the need to go for the “back up” first.

If you reach for the little gun first, it’s not the back up.

Did you check out the Judge Public Defender? I thought it had a more compact frame size than my standard Judge.