RE: Buckshot
The more pellets a load has, the more effective it should be, since there is very little differrnce in muzzle velocities of any shotshell (from 1100 to around 1350 MAX). BUT THERE IS A REASON FOR BUCKSHOT BEING PROHIBITED FOR HUNTING DEER OR LARGER GAME IN MOST JURISDICTIONS!! It has a very limited effective range, no matter how many pellets a load contains!!
Pellet SIZES are uniform between brands of U. S. made ammo!! Some European shot having the same number as a U.S. made pellet may not be exactly the same diameter, however!!
Quilly, if you found shot of two different sizes in shells both marked " 00" , well one of them was NOT " 00" .