I am getting ready to buy my son a gun to turkey hunt. I know that I want to buy an 870 youth model for him. But I noticed that Remington makes the 870 youth model in a 16 guage that is 2 3/4 only. Would it be better to buy him the 16 guage 2 3/4, or would it be better to buy a 20 guage that shoots 3". How much selection is there in ammo for a 16 guage.

I'd go with a 20 ga. There just isn't all that much ammo out there yet for the 16 ga. If you reload on your own, it might have some merit. Another thing you might want to keep in mind is that there's not much, if anything, out there for 16 ga. turkey chokes.

My daughter shoots the 870 youth 20 gauge. The thing throws a nasty pattern with a hastings turkey choke and Federal #6 3" turkey loads. 15+ lethal hits at 35 yards.

I'm a 16 guage fan, so I'm a little biased

I have no problems finding loads for turkey for my 16 guage. Remington Express in #4-#6 is plenty capable of killing a turkey. Also Kent makes some excellent 16 guage loads, http://www.kentgamebore.com The shells don't say "Turkey Load" on them but they are getting 13000fps which is as fast as a 12 guage 3" Winchester High Velocity load.

I get my Remington Express at Dick's here. I don't know about your selection in your area though. If you can't find 16 guage locally then the 20 guage might be a better option.

have you though about a 12 ga. the 20 ga with 3" loads is equal to the 12 ga. 2 3/4 as far as the kick goes.then the 12 will grow with him for years to come.
get a 12 ga. 3" and he can shoot 2 3/4 shell till he grows to it.
Just a though.that what my dad did for me some 40 year ago.

luck on which ever you get.