I am just curious Jay, instead of switching shells when you were using your 3" at ducks, why didn't you just use #2's like you are doing now with your 3 1/2"?
gunsaholic, the simple answer is 'pattern density'... I am a big believer that you MUST hit game animals with pellets to cleanly harvest them. If I simply used a 3 inch # 2 shell, it would have less pellets in it than a 3.5 inch shell loaded with #2's...
I remember when steel first came in, everyone was freaking out, saying how it didn't kill cleanly... Guys used to use #4, #5 or #6 lead pellets... They went to BB, BBB and even T steel shot sizes... What happened as a result... When you did hit a bird, you hit them with very few pellets... Lots of crippled & missed birds with patterns that had very thin densities... NOT enough pellets!
So, I started shooting #4 steel for ducks & guys hunting with me SAW that it worked! They stopped using the HEAVY HEAVY shot sizes & started realizing the same success with smaller pellets (#4 steel) and a higher pattern density that I was seeing...
And, in the last bunch of years, I have been getting into a more situations where ducks and geese are seen as a mix... I used to use #2 steel in 3 inch shells for geese... With a 3.5 inch shell, it now allows me to simply shoot #2 steel pellets for geese AND ducks without losing too much in the way of pattern density for ducks...
The 3.5 inch steel shell I shoot with #2 steel has 1 &3/8oz of shot, that's 172 pellets...
The 3 inch steel shell I used to shoot geese with #2 steel had 1 &1/8oz of shot, that's 140 pellets...
The 3 inch steel shell I used to shoot ducks with #4 steel had 1 &1/4oz of shot, that's 240 pellets...
So, a quick look at my math shows you that the 3.5 inch shell is a compromise for me... It allows me to shoot heavier shot & split the difference wrt pattern density... Hitting them with a heavy enough pellet is important! But pattern density is also important!
Cheers
Jay