I know this is an old thread, but I found it while researching a related topic and thought I might throw in a couple of comments.
First of all, regarding that 13/16" barrel, I would not even consider using a vent liner. Just drill the hole. I have four flintlock smoothbores without vent liners that shoot just fine. I had one flintlock rifle (sold earlier this year) that had a 7/8" barrel in .50 caliber. Despite the fact that I specifically requested no vent liner, the builder (a very well known and generally respected one... who will remain nameless...) installed a White Lightnin' vent liner anyway, assuring me I "would not be happy without it." The liner did not make ignition any faster than the smoothbores mentioned above. However, it protruded into the bore and created fouling trap. Accumulated fouling (i.e. carbon) can potentially hold a spark, like the charcloth in your tinderbox, increasing the risk for an accidental discharge or "cook off" during loading. The vent protruding into the bore also prevented getting a jag to the breech face, which complicated cleaning. Furthermore, I had some concern regarding the number of threads in that thin barrel wall holding the liner in place. These vent liners, coned from the inside, undoubtedly have some value for rifles with thick walls at the breech, but for thinner barrels, it is my opinion that they are unnecessary and may potentially be a safety hazard.
Anyway...
My dad had a respectable gun collection when I was growing up, including four Tennessee rifles. These are still in the family, although I am not actually in possession of them. I was able to convince Dad that I was deeply interested in muzzleloaders and especially southern rifles, and that I was responsible enough to not damage them, even in my teens, and he allowed me to take them apart and examine them in detail. This would have been in the late sixties. I made notes but these have subsequently disappeared. However, based on my admittedly faulty memory, I will submit the following:
One rifle was stamped "J.J. Pryor." The others had no maker's mark that I recall, although one had a silver plate let in the top flat of the barrel with the name "Grimesly" engraved in script. It is my understanding this would more likely be the name of the owner than the builder. All four were percussion, and it is my opinion that they were authentic mountain rifles from the late nineteenth or possibly early twentieth century. I was not savvy enough at the time to determine if any of the locks had been converted from flint, but I don't think so. However, it is important to note that our pioneer forebears were thrifty people. Old locks would be saved and refurbished. A late 19th century rifle might be fitted with an old flint lock, converted to percussion. This does not mean the rifle was originally a flintlock. This should be taken into consideration by anyone thinking about reconverting an old rifle back to flint.
Two of the four rifles were stocked in curly maple, and two in walnut. The Pryor rifle was in walnut, the Grimesly in fantastically striped maple. The Pryor rifle was a fullstock, while other three had been cut back to half-stocks. On these, you could see where the dovetails for barrel tenons had been hammered flat, except for the dovetail nearest the muzzle. On all three, this held a ramrod pipe, made of heavy sheet iron folded into an "omega" shape, with the base filed to fit the dovetail. All four rifles had poured nosecaps with cutouts for decoration, if I remember correctly.
Two of the rifles had hand-forged barrels. Interestingly, the top three and side flats on these were smoothly finished, while the lower three flats, which would have been hidden by a full-stocked fore-end, still bore hammer marks. This was likely a time-saving strategy employed by the gunsmiths. I recall that the full-length hand forged barrel was slightly swamped. The hand-forged barrel on the Grimesly rifle was tapered, but I am quite sure it had been shortened, cut off at the "waist" of the swamped barrel. The three full-length barrels were all in the neighborhood of 44". Sorry I don't have measurements, but I can assure you all were pretty heavy. It would have been possible for a strong man to shoot any of them offhand, but believe the old-timers would avail themselves of any convenient rest when possible. Ruxton frequently described the western mountain men propping their rifle on their wiping sticks in the absence of natural rests. Two of the rifles were small caliber, maybe .31 to .36, but I don't remember precisely. The Pryor rifle was about .44 caliber. It was still shootable, and I did shoot it. The Grimesly rifle was about .53 caliber. It was marginally shootable, but as the Lord watches over fools, I shot it too, and lived to tell about it. All barrels had seven grooves.
The Grimesly rifle had a classic "lollipop" tang, extending all the way to the comb. The other three tangs were shorter, and at least one had been forged to taper down to a point. I don't remember about the others. I'm sure all were fastened with wood screws... None were through-bolted to the trigger plate, if I remember correctly.
All four rifles were iron mounted. All four had buttplates. One was missing the lock, triggers, and trigger guard, but I found a hand-forged triggerguard in a box of my Dad's assorted parts. The screw holes lined up, so I put it on. All triggerguards were screwed on... none were pinned. All of these rifles had double set triggers (you could tell by the mortise in the rifle with missing triggers that they had originally been double-set). The intact triggers were all single-phase, and none of the locks had a half-cock. I believe this was probably standard practice, back in the day, as I have seen this on other old rifles, as well. In any event, the triggers had to be set before you could cock the rifle, and the hammer could only be full-cocked or fully down.
The Grimesly rifle had a "banana" patchbox. None of the others had any sort of grease-hole or patchbox. I don't recall a cheekrest on the Pryor rifle, but I believe the others had straight, "Tennessee" cheekrests.
In his book, The Plains Rifle, Hanson mentioned an "eastern bear rifle," and he postulated that the old Tennessee rifle was foundation stock for the later "plains rifle." I think our old Grimesly rifle is a clear example of the transition... Larger caliber, shorter barrel, and cut to half stock, but of an obvious "Tennessee" pedigree. This was a very fine rifle, in its day.
Regarding flintlocks, I had it in my mind back in the seventies that I would build a southern flintlock rifle. Like many of my schemes, this one never came to fruition. However, I did order detailed "blueprint" drawings of a flintlock Southern Mountain Rifle from an advertiser in Muzzle Blasts. They were based on a rifle in the Neumann collection, and I believe the actual rifle was pictured in one of Mr. Neumann's books. These drawings were unfortunately lost in a move, but I studied them enough back then that I still recall a few details. While the drawings were excellent, the rifle they depicted was not what I expected. Rather than a long, slim, flintlock version of the Tennessee rifles with which I was familiar, this one had a shorter, approximately 39" barrel. I recall the breech was square (not octagonal), and I believe it transitioned somehow to round. It had a big bore, over .60 caliber, and I believe the artist said the rifling was still intact. This rifle had an enormous, round faced English lock. The artist recommended the Pedersoli Lott lock for those wishing to recreate the rifle, as this was the only similar new lock then available. The rifle had a single trigger. The guard had a simple bow with no grip rail and had apparently been salvaged, along with the ramrod pipes, from a military musket. There was no buttplate. The curving cheekpiece may be best described as a "crescent." Take a look at the cheekpiece on Jim chambers' "Little Feller's Rifle" to get an idea. I wish I could find those drawings...
If you're still with me, thanks for reading. My memory is not entirely reliable, but to the best of my recollection all of the above is accurate. I hope some may find it interesting.
Best regards,
Notchy Bob