I'm not sure what the optimum muzzle velocity should be , but the PDX1 410 shells quote the velocity at 750. I'll try and do a little research on it, or maybe one of you monkeys already know this.
I will try and do a comparison for you along side a 38 snub nose. But I'm definetly wanting to know the ranges as well. I'm like you , figuring the range on the shells isn't going to be that great, 50 feet like you said is about what I was figuring. Also wondering the accuracy of the 45 shells behind the 410s.
With such a short Barrel, compare to what the normal Barrel Length, that a .410 Shot Shell is loaded for, most of the Powder will remain Unburnt, and just blown out of the muzzle, once the wadding leaves the muzzle... This unburnt Powder does nothing to add to the muzzle velocity, of the Shot, or Slug, except make a BIG Blast out in front of the muzzle... When Reloading for these short Barreled Weapons, you will want to use the Fastest Burning Powder, available... For Pistols, I really like Bulleye, as it is about the fastest burning Powder made...