RE: Shotgun barrel length?
well im not big duck hunter, but i know a tiny bit about that
duck: modified choke, 3" steel loads...shot size:5-6....other guys might know better
turkey: full choke, 3" lead or those expensive non toxic loads, shotsize: 4
dove&quail: improved for tight cover, modified if your shots will be longer, 2 3/4" express loads in 7 1/2 shot size should work well, maybe 8's for doves
rabbits: improved for tight cover, modified if your shots will be longer, 2 3/4" express loads in 6
skeet: improved, 2 2/4" cheapest loads you can find, size 8 shot is good.
these are just my preferences...other
you use a modified choke with steel shot because it is not a "forgiving" as lead and it shoots faster.....if that was done in a full choke you can damage the barrel by the pressures that are generated behind the fast moving steel loads that dont compress as it gets forced out the smaller diameter.
eating a tiny piece of lead here and never never hurt me....but it is known in the state of california to cause birth defects and reproductive harm....so it is good to check over the meat. plucking the little ball of lead out then cooking it up and eating it (the meat, not the piece of lead) wont hurt you any.
btw, i know many people who hunt with a 28" barrel. i would not worry about a shorter one unless over the next season or two you feel that you would benifit from shorter one.
hope that helped,
Bob