How much difference do y'all see in the different length of shells (given everything else is the same)?

It's noticeable to me. But I'm getting older and my shoulders are shot (). I will keep a 3" in the #3 spot for ducks or pheasants as an insurance policy or to punish myself for missing twice - not sure which. When I know its coming I tend to tense up a little more.

Nothing like the jump from a 2 3/4 dove load and a 3.5" BB though.

About a quarter inch.

20-30% more recoil.

Steel 6s and 4s 2n3/4" 1n1/8oz. Plenty of pattern density up to steel 4s to shoot as far as it will reliably harvest teal or ducks.

Steel 3s to BBs 1n1/4oz in a 3" hull. Adjust shot size to game. 3s work as far (and some days farther) than I can reliably hit a duck.

if goose hunting where you are actually targeting a larger bird I can understand shooting 3" shells. Otherwise, definitely no need for it. 2-3/4" 4s, 5s, or 6s is all that is needed. Good 1-1/4oz loads can be found in the 1300 fps range. Especially if you get them in something like bismuth, hevi shot, or anything that is heavier than jank steel. Shell companies advertise steel shot with phrases like "high velocity, speed ball, super speed, MAX Dram Equivalent." And that's because they have to do that for steel to be very lethal at slightly longer ranges. By making loads that "hot", it often does nothing but blow a pattern out beyond belief. If you can't kill'em with the loads I mentioned above, especially 5s or 6s, you need to improve your hunting skills, shooting skills....or both

If you can't kill them with steel and are shooting bismuth or hevi shot you may need to work on your skills also

not impossible, but not easy to find a 2-3/4" steel load that is not 1400 fps, and if it isn't it will more than likely be 1-1/8 oz. Not to mention shells for the 28 gauge. I reload because it is something that I enjoy doing anyway, and it doesn't cost that much more to load bismuth instead of steel....so why load steel? Hits harder than steel ever dreamed of, and doesn't have to leave the barrel at subsonic speeds to CONSISTENTLY be lethal at 50yds

I don't think the average duck hunter can afford hevi-shot or bismuth. I shoot Kent Faststeel 3" #3s and I feel like they are plenty lethal for the ranges I shoot. I can honestly say that I have never thought about recoil when shooting a bird, so the extra thump from a 3 or 3.5" shell has never bothered me. I shot a lot of 3.5" shells when I was in school and shooting Canadas and cranes, and I never had a sore shoulder.