Shell lenght ???

[skeet]

If you buy a 3" gun, that will probably be all you need for 99% of all your hunting. Fabs is essentially right. You may have a longer killing range with a 3 1/2" gun but not enough to make a major difference in deciding the gun and shell length to buy. if you end up buying a Remington 870 express, they make it in 3 1/2" also. If it doesn't cost more than 25 bucks or so more, buy it. Then as Fabs said...you can shoot any shell length through the gun. Most of all, what ever you get, Have Fun!!