Just purchases an Ithaca Model 37 Police 12 ga. Built in 1969. It's a four round mag model with rifle sights. When I load it, half the time it freezes up and I can't chamber a round. I attempt to move the slide release, which doesn't seem to move much at all, and no effect. Then it decides to free up and chamber a shell, rather nicely. There are no other problems, cycles fine on the ejection cycle. It just hangs up when taking rounds from the magazine. What have I got going here? Thanks. Love the gun but for HD it's gotta cycle. I took it home tonight, oiled it up nicely, and will return to the range tomorrow with different ammo.