Thats true if retained velocity and mass for penetration is the limiting factor, ie waterfowl hunting.
I'm constantly amazed at hunters who use (lead) #4's and #5's for turkeys.
Why?
It CAN'T be pattern density! In fact, the omnipotent Mr. (Tom) Roster has claimed that #4's don't throw a pattern dense enough to reliably kill turkeys. His observation, not mine.
I'm quite sure that if a #4 lead shot reaches the brain or the spine (central nervous system - CNS), the bird will die.
But Im not sure turkeys are the same. Someone compare a good modern bismuth waterfowl shell to an equivalent lead turkey load and see how they compare.
"... But I'm not sure turkeys are the same. ..."
They are the same in that they are birds.
"... The main distinction everyone seems to be overlooking, is in the shooting! ..."
WATERFOWL is taken on the wing. You shoot at "the bird". Not necessarily a specific part of the anatomy. I've seen waterfowlers burn all three (3) of their Federally allocated shells to anchor a bird. Feathers flying, bird climbing until that one pellet eventually contacts brain or spine.....and they don't always hit the ground dead!
TURKEY'S, on the other hand are normally shot standing still. Specifically with a shot to the head (brain) or neck (CNS)! You do not need to teach an 8 year old to wing shoot to kill a turkey!
What DO you teach?
Put that red dot on his head and pull the trigger!
A turkey's head is about the size of a quail. It's also about the same density as a quail!
If it's "logical" to shoot #8's, or even #9's, at a quail (pattern density), why isn't it logical to use #8's (pattern density) on turkeys?
Yes sir, a turkey is a big bird, but you aren't shooting at the "turkey" proper, you're shooting at his head or neck!
Pre TSS, everybody was shooting 4's, 5's and 6's, mostly #5's in magnum 3" and 3.5" ammo! I know! I've seen 'em do it!
Now that TSS is on the scene, what is everybody shooting?
TSS #9's!
Why?
"... PATTERN DENSITY ..."!
I know! I've seen 'em do it!
One buddy was amazed, and according to him lucky, that I killed turkeys with 1 1/8 oz loads of #8's with one shot! The three I called in for him, ALL required 2 or more shots of lead #5's in a 3.5" (Mossberg 835) shell!
Was never able to convince him not to body shoot a turkey!
"... Pattern Density kills! NOT shot size! ..."