[au2183]

Separate the halves and see if it still seems to catch. I would think you would be able to see where it's hanging up by placing the lever in that position with it apart and looking for a notch, etc?

 

[au2183]

That's great news! I have purchased several things from Wisner's and they are great to do business with. I have several 39A's in various configurations, and I'm always looking to add to that collection. It's getting real hard to find one for $300 in any condition, so I'd say you got a fine deal!
Take a chore girl or similar brass or copper wool product, not steel, and some gun oil or Hoppe's #9, and you can gently scrub that rust freckling away with no damage to the bluing beneath it. If it's not through the bluing it may disappear completely. Good luck with that wonderful piece of history! I think the 39 is one of the finest guns ever built, of any caliber!