Being alittle hard on the kid aren't ya Nomercey,heck it's a good standard for a kid just learning to hunt.

So to your question 20gaNate,my vote is the same as bigbulls.The Winchester 1300 is hands down one of the most dependeble shotguns on the market.
I got mine when I was 13 a 12 ga,with 28 in. barrel,and I don't know how many pheasant,ducks,geese,turkeys or grouse that gun has killed but it has been a pile.I shoot a Improved Modified choke in it and it has preformed with out a flaw.
So if you wan't a 20ga. in that same gun I would go for it,the stores around here sell them for about $219.00 on sale in the fall and about 269.00 the rest of the year your choice of bore.
Happy hunting,and "Gitter Done"