Ron called it. Iver Johnson Champion is a shotgun. Yours is 12 gauge and is most likely chambered for 2 3/4" shells (12 gauge normally can be found in 2 3/4, 3 and 3 1/2" chambers - you don't want either of the last two). It's a cheap gun - a Chevy, not a Cadillac - but just like a Chevy, it's good, just inexpensive. Probably has a 30" barrel. Great for shooting squirrels. Not bad for ducks. A little long for the turkey woods and the choke's a little tight for quail, but it'll get the job done if you do your part. My uncles kept my Mama's family fed, during the Depression, with an Iver Johnson Champion. 'Course, I'm sure they were shooting game out of season and shooting pheasants on the ground. But they brought home the meat.
Meddle not in the affairs of dragons, for thou art crunchy, and taste good with catsup - George of Lod, Year of Our Lord 297
I always take precautions.
Beware the Evil Bullet Fairies.