An interesting topic. After reading this post and the other one re: "off face" I set up a precision vernier caliper to read .000". Holding it up to a light, I can't see any gap. Then I set the caliper to read .001" and I can see a very distinct gap, parallel between the reading faces of the caliper. A gap of .002" looks pretty big when held up to a strong light.
Back to double guns, the barrels would have to be absolutely PERFECTLY fitted in order not to see a gap somewhere. Actually it would have to be an "uniform contact fit" as the term is used by machinists, and there would have to be a gap between the barrel flats and water table to allow that contact fit to be maintained over time as you open and close the gun. If absolutely no light could be seen between the back end of the barrels and the breech faces when the gun was new, it would likely show some light at the bottom when the gun was used a while.
LIkewise, if the machining and fitting were just a thou or two off when the gun was assembled, you'd probably see a gap here and there. Wear of the hinge pin or hook would have nothing to do with it.
Mr. Cherrybomb says the gun will close on a thin sheet of paper. That paper will compress when the gun is closed. I wonder if the gun will close and lock up if a .004" precision steel shim is inserted instead of the paper? If the gap was as thin as he described, I doubt it. Silvers
