Have you ever seen what 12g bird shot does to a human body from a 10-15 foot distance?
I have----Not Very Pretty!
If closer, then it's Plain Ugly!
Yes, birdshot can produce horrendous surface wounds, and can certainly be lethal if you're close enough.
00 buck can be effective out much farther. To see the damage to intermal organs requires an autopsy.
LOL, short bbl'd pistol grip and birdshot, huh?
Once watched a couple gang banger types try out their new pistol grip only shot gun. Admittedly, they had little experience with it, but when they'd fire at 10ft from the hip (they'd brought a bunch of phone books) they'd miss. When they tried to operate the slide the gun would turn at a 45 deg. angle and the slide wouldn't operate until the second or third try.
Yes, with practice that kind of performance can be greatly improved upon, but the pistol grip only shotgun's performance is much less efficient than a stocked shotgun. They were designed for storage in small places.
After that, they had to try out their new 9mm by unleashing rapid fire shots at no particular target in the general direction of a dirt bank.
Hope my comments aren't interpretated as taking such individuals lightly. Just making an observation.