Disclaimer; I will admit that my information concerning ammo velocity's and such is almost null. I'm changing that slowly.
I read recently that a FMJ .380 would have more velocity out of a barrel, such as the one in the Bersa Thunder, than a .38 FMJ out of a 2 inch snub.
Is there any truth to this at all? I kind of doubted it, but...well. Refer to my disclaimer.