hi rusty -
i favor my 410 synthetic handi over anything for fun shooting, but, i would not hesitate to get my son a side by side or O/U shot gun if he was ready for one.
on the other hand, i would not buy him a pump or autoloader.
in my humble opinion, there is nothing sweeter than a 410 side by side with double triggers when you are out on a cool sunday morning in full dress going after bob whites. the morning fog has already burned off, but you can still see the dogs huff and puff little clouds as they cover ground. you and your boy bag your limit and then go home to talk about the day.
my youngest son is becoming quite the wingshooter. i would not let a few bucks either way deprive myself of the time we spend together hunting birds. if he wants a O/U, or SxS, or Pardner, get it and hunt with him as much as possible, as soon as he goes off to college, or get's married, all that will stop except on occasion.
the gun your son hunts with is just one part of the whole experience regardless of gauge or barrels. my sons' first gun was a 410 pardner, the first time out, he bagged a bunch of bobwhites, and he prefers his pardner to any of my brownings, poli's, parkers, or guild guns.
sg