My friend has a Citori O/U 12 ga. he uses when we shoot sporting clays. It's a few years old, and he has noticed over time that it has been getting harder and harder to open up. For our round yesterday, he shot my 725 and did better than his usual, so that was one positive aspect of this.

When fully assembled, though, his takes quite a bit of force on the top lever to open, and occasionally when closed it gets into a mode where it takes both of us to operate, one holding the gun in place and the other pushing as hard as we can on the top lever. Sometimes when stuck, it takes 10-15 minutes of fiddling to get it to open.

Details below. Anyway, if anyone has any ideas as to what to check/fix, I'd be most appreciative.

Details------------------------------
I have a slightly newer Citori 725 which is a little different internally to his model Citori, but not fundamentally different in how the gun latches or pivots. We took both apart and compared to see if there was anything different about the fit or action. First we checked the force for both levers with the gun taken apart and both top levers took about the same, slight force to operate and the little latch slid back and forth indistinguishably from one another as the levers moved.

Two differences on his versus mine:
1) when his was taken apart we noted that the barrel lug on his barrel where the forearm connects to the barrel had some shiny areas and is a little beaten up. Mine looks showroom new. Both have put thousands of rounds downrange.

2) when putting his shotgun back together, when we use the latch to lock the forearm in place, it takes some force to engage.

Noted for completeness but most likely irrelevant:
Both shotguns are stock, other than my having swapped out the two little springs inside the forearms on both of them with lighter springs (1911 firing pin springs, as I recall) so the spent shells don't go into orbit when the gun is broken open to reload. As both shotguns were done in the same way, with the same springs, at the same time, and mine is working fine, I am not suspecting this as a factor, just passing the data along just in case.

Once it is opened then closed, does the lever snap closed like normal?
Just spit-balling if the spring might be broke. Keep us posted what the fix is.
Who knows, I have a 625 that might develop the same thing in another 20k rds.

Is it difficult to open when the forearm is removed? If it opens easily with the forearm removed that means the forearm iron is not fitted properly, possibly because someone has peened the forearm iron to tighten up the fit. Tightening a shotgun by peening is NOT the correct way to tighten up a fit and is a problem prone sort of solution. The correct way to correct a loose shotgun is to replace parts with oversize versions or replace the hinge pin.

The Citori is a very robust gun, I would send it to a gunsmith

Thanks for the ideas. We have found a local gunsmith (two, actually) and we are taking it there tomorrow to have it looked at.

Will advise.

Well, the local gunsmith looked at it, worked it a bunch of times and said he had felt a bit of a burr in how it operated. After he'd done that, it would open repeatedly with the top lever kept to the right and we could not get it to lock up.

Gunsmith recommended putting a bit of lithium grease at the hinge, so we stopped at the hardware store on the way back and picked some up.

I'll keep an eye on how this works out, and let you know if that turns out to have fixed things.

Sounds like a happy ending.

Good to hear.....