The gun has some very small wear every time it is cycled open and closed. Suitability of lube, cleanliness of lube, finish to the steel parts, and fit of the parts are the more important factors. Hard (either case of through hardened) parts that are fitted over a high % of contact area with a very polished" finish and running proper, clean lube will cycle a huge number of times.
Each firing of the gun flexes the action slightly and causes movement between mating parts such as the hinge pin and hook, locking bolts and bites, and circle joint and frame. The amount of flex is goverened by design and firing pressure. The stronger the design and the lower the pressure the less the flex. Wear is goverened by the size and number of flexes, lube, and hardness of the steel. To mitigate wear, keep pressure down, keep lube clean (assuming any good, modern oil or grease), and limit shooting of any gun that is already worn enough to be "slightly" off face.
As usual, Don answered the gentlemans question in the fewest possible words and as usual, hit the nail right on the head in more ways than one.
When I first got into doubleguns....I was instructed to hold the lever over and close the gun...to treat the guns mechanism like you would when closing the "lid" on a fine pocket watch. And so I did, for awhile. Then after I got into the doublegun thing a bit more I went the route of closing the gun gently and letting the springs do the work of locking the gun. I cringe everytime I see someone afield or on the range slamming their guns shut, if they are interested..I will offer advice on correcting that nasty habit. The only double gun that I own where closing the gun gently isnt in its vocabulary is a Lancaster Model A, if you want to close it, there's no doing it gently...I dont slam it shut as hard as I can.. but I do close it with just a bit more gusto than normal though.
Dustin
