I don't know a thing about the Ithaca 51, but I have a Remington 11/48 in 12 gauge. It is a solid shotgun. You don't see barrels everywhere, but I found a 26" IC barrel for it on Gun Broker. The Remington is in very good shape and is a very usable shotgun. I never noticed any more kick with it than I would expect with a Browning Auto 5. It doesn't kick hard but you can tell that there is a lot of stuff going on during the recoil. I'd go for the Remington 11/48 and pass on the Ithaca 51.
