claymore1500 or whomever else can help
Ok, I will give this a try, (I was going to say " going to give this a shot" but I decided it was a bad pun, so I didn't)
Anyway, I (Like I said) have looked at bond arms, and they are just too big to suit me, The american derringer is more traditionally sized, Mine was bought used, so I didn't have the choice of calibres, but chances are I would have picked the .45acp anyway as this is just a fun gun, not so much for carry.
It should be noted that these CAN hurt your hand, It states in the manual to limit shooting to just a few at a time, I am 6'4" 240# heavy truck mechanic and if I may say so, my hands are used to impact and very strong, so I can shoot a box at a time with out even feeling it.
That said, for the intention you stated, I might suggest one in .357mag, due to the fact that if you want to make a day at the range with it you can shoot .38spl.
They are accurate within thier accepted range, as far as the few people that claim you will do better with a .38snub nose, I agree with respect to capasity, but disagree with range or power, let me explain, THe snub with a 2 in. bbl. compared to a derringer with a 2 in. bbl., the derringer will give you better ballistics due to no cyl. gap so no loss of energy from gas bleeding off, it may only be a few feet per second, but that will translate into deeper penetration and better bullet performance.
There was a time when there were rumors of american derringers went out of bussiness, not true, the web site was down but they are back up and very much in bussiness.
Also, please note, My opinion of bond arms is just that, my opinion, they are well respected and well made, just too big for my taste.
The davis/cobra line is fine if you are looking for a small cal. but I think that the larger ones MAY beat themselves to death due to the alloy frame and barrel assemblies (see my previous post) the one I have seems to be well made, every thing is tight, even though I have fired hundreds of .22lr. through it over the ten or so years I have had it.
If you have any more questions feel free to pm me and I will try to answer them, I am not a derringer expert by any means, but I do have some experience in the field.