As an engineer myself, I agree with your engineer friend. As a restorer of double guns and maker of springs, I can add this. I see many guns that have been sitting unused
and left cocked for decades. When I remove the parts, clean and then reassemble, the springs are just as good as when they were made over 100 years ago in most cases.
Also consider this, most people at the turn of the century didn't use their guns any where near as often as we do today, with clay shooting and all, I would wager most were all kept in the
cocked position, when put away.
Sir;
Your comments about observing the conditions of V springs that were made in past centuries brought to mind the observations that I have made on old classic V springs especially side lock mainsprings by the lock makers decades ago and the one thing that I immediately look at on a mainspring to judge the merits of the original spring maker. And that is when the mainspring is in full cocked compression is there significant clearance between the legs of the mainspring so that the mainspring legs do not touch each or and more importantly not bind against each other--at any time, even over cocked to maximum. Then secondly when I have the mainspring in my hand look to see how well the polish of the legs of the spring was done on the inside of the legs--down into the "far reaches of the u-bend" of the spring that had to be polished before the spring was heated and formed into a V. The old spring makers also knew how to form the legs of the spring in the correct taper to ensure long life--creating " a spring energy battery". This tapering of the spring legs to prevent undue stress points along it's length to maximize energy and create long life of the spring and at the same time minimize size might just be called an "art", with just a little science and "engineering" added to the elixer. But of course since you are a spring maker I am just reviewing what you already know.
Kindest Regards;
Stephen Howell
