RE: Ithaca Mag 10
Keep an eye on the gun's condition, here is what the Gun Digest says:
w/ vent rib barrel Perfect-$700 Excellent:-$570 Very Good:-$490
w/plain barrel Perfect:-$650 Excellent:-$520 Very Good:-$440
(add about $20 to all if it is the Deluxe version and $150 - $200 for the Supreme version)
As far as the jamming, I am in no place to speak on the issue, know very little about autoloading scatterguns, never really cared for them. Good luck either way.