Now we attribute hormones to the gunmaking business.
Very interesting! Maybe more truth here than we'll ever know.
On a more serious note I'd point out that regional differences were as natural then as they are today. Look only as far as language. I moved from Northern NY to the Twin Tiers and found out that certain terms and words were used differently with just a 150 mile difference. Go south into PA Dutch country and you again see a change. South again into the Washington area brings yet another.
The theory about folks not traveling as far afield then as today is somewhat of a misconception. I agree that one couldn't hop in a car and head for California, but there was no lack of travel. Consider the Revolutionary War... (I'll use the Sullivan-Clinton Campaign as an example.)
Troops serving in the Mohawk Valley were moved to Cooperstown where they dammed the outlet of Otsego Lake and thereby raised the water level several feet. Meantime a contingent of troops from Pennsylvania were posted to the Wyoming Valley. Long about mid August the dam was broken at Cooperstown and Sullivan's army rode the river crest down the Susquehanna to Tioga Point (Athens, PA). There they met Clinton's army and then proceeded to decimate the native farms and villages in western NY. There had to have been close coordination to accomplish this feat and the distance involved is considerable even today.
Troops involved were from everywhere in the colonies with the possible exception of the deep south. Their march into the Chemung Valley, the Finger Lakes, and westward impressed many of them enough to come back as settlers after the war. The fact is that many returned via virtually the same route they had taken during the war.
My cousins, the Wordens and Starks, were Yankees. Their route was via New England, into the lower Hudson Valley, then over the mountains to Wyoming, and finally north along the Susquehanna. Their headstones in our little cemetery would seem to indicate that they wasted no time in getting here after the war.
Another family by the name of Seeley traveled a different route. Ebenezer Seeley served in the F&I War and lived just outside Montgomery, NY. (I have his powder horn.) His two sons served in the Mohawk Valley during the Revolution and likely took part in the S/C campaign or heard of this area from others that were here. They came along the route from the Mohawk Valley and down the Susquehanna.
The long-winded oratory above (I apologize) serving to point out why a rifle made in Owego, NY could easily be confused with a lower Susquehanna piece, yet hint of New England influence. The opposite being the case north of the central Finger Lakes where NY/New England rifles might show a PA influence. This being especially the case after a generation had passed and these small "mixed" communities began to establish their own unique identity.
Perhaps we might conclude that travel caused the differing variations among our long rifles, not the lack of travel. And by 1840 technology and the ease of travel began the decline of the firearm as a unique expression of community.
I could never understand why so many folks aren't interested in history. There's so much to be learned and appreciated.