Ted, there are various reasons for making a sidelock in addition to the intercepting sear. One is the ease of accessing the "guts" of the gun, especially if the locks are hand detachable. Another is leaving more "canvas" on which the engraver can do his thing (although that's also true of sideplated boxlocks). Another is that--at least per the British, who contributed so much to the development of the modern sxs--the sidelock is a superior design. And there are those who will contend that in general, you get better trigger pulls with a sidelock vs a boxlock.
But our gun industry focused on numbers with only a tiny percentage of their output represented by the "best" guns they made. In contrast, there were several British makers who made their names based on a much smaller number of "best" guns. So a very different approach to the business. In this country, no one ever adopted the business model of "best" guns only. Or mostly.
Larry,
I was thinking in terms of good reasons. The shear numbers of guns built on the boxlock design, in contrast to the numbers of sidelocks, that function perfectly, 50-150 years after they were produced, sans maintenance of their "guts", to use your term, would seem to throw so much cold water on the notion that being able to see them more easily is an advantage.
Engraving, much like the "canvas" of the design of gun it is applied to, is very subjective. I have seen stunning examples of engraving on either design, and, much more that was not so. On both types of guns. I wish people who can't do it would stop trying to do gamescene engraving. Not everyone is Winston Churchill
I have seen good, and horrific trigger pulls in all types of guns. I will suggest, that, at least in the case of English guns, a sidelock would have more time spent by a higher skilled worker on it's triggers than you might expect on a keeper's boxlock. There would be exceptions, but, not often. That doesn't mean a boxlock can't have wonderful triggers. Far from it.
A hammerless sidelock is simply a hammer gun with it's hammers on the inside. As to it being the best or not, comes down to who built it, and not the name that is on it. We have seen examples of "name" guns, that are not the best examples of what said name was supposed to stand for.
Best,
Ted
