I can tell you that here on the Eastern Shore of Maryland that the vast majority of frontstuffers use inlinesd. I sell the darn things. In the last 5 yrs I have sold exactly 5 sidelock guns...and only 1 was new...the others were trade ins. In opposition I sold 23 Savage(just the one brand mind you) 10ML guns last year alone. The muzzleloading fraternity here is almost all comprised of hunters.... and the inlines are much better hunting arms...maybe I should say more reliable. It's like archery... Now we have people getting into the crossbow thing. They mostly learn very quickly that they are still shooting a bow. No real added range...just easier to aim. But for hunting the inlines have it all over the sidelocks in reliability and ease of use with scopes etc as well as the pellet thingies and 209 primers
Maryland is kind of overrun with deer and the DNR here wants to make it as easy as possible for the everyday Joe to be able to get his deer...if he can find a place to hunt