I have a 1960 era Gamba double with extractors. When it opens it stops before it has opened enough to either load or extract shells. The barrels can be pushed down easily so that it is open far enough to load or extract. However, it feels as if the final bit of opening is spring loaded. It won't remain fully opened unless I push down on the barrels. I don't believe the gun was shot much. Is this a mechanical problem, part of the design or does it just need more shooting to loosen it up? Thanks.