Stupid question, Old Ithaca/New Hasting 3" barrel

[kentucky_smith]

So I got a good deal on a brand new Hastings Wadlock barrel for my Ithaca 37. It'll chamber a 3" shell, but of course the gun is too old to be for 3 inchers.

Haven't tried fit yet, but why wouldn't a 3" shell function in this gun? Too hard on reciever or bolt? Ejection port in bottom and carrier too small?

Just talking out loud until I can get out and pattern it.