An earlier 12 Grade 3 with ejectors and Nitro Proof barrels. My first question might be this- when you open the gun, do the hammers stay cocked back and are the ejector hammers cocked as well? If the ejector luggers protrude and will not slide back with their guide pins into the breech face, you need a good gunsmith's services, such as Bachelder or Buck Hamlin. But if the gun stays cocked as you open and close it, I would insert a set of snap caps, dry fire both barrels, and open it- If the hammers recock and also the ejectors kick out the shells, that should release the roller latch.
Indeed, a fine early LC Smith--
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