Joe,
Just some bbl. length suggestions and loading data to keep you busy...
Regarding modern 4 bores, the October Country heavy rifle is "30 inches long and it is 1-3/4 inches wide at the breech and tapers to 1-1/2 inches wide at the muzzle". The rifle weighs 18 pounds.
In The Rifle and Hound in Ceylon , Samuel Baker notes that "My battery consists of one four-ounce rifle (a single barrel) weighing twenty-one pounds , one long two-ounce rifle (single barrel) weighing sixteen pounds". Clearly, it seems that Baker was concerned with the ability to burn all his powder and tended toward longer bbls. This can be seen again below.
In, Wild Beasts and their Ways he states, "In 1840 ... I drew a plan for an experimental rifle to burn a charge of powder so large that it appeared preposterous to the professional opinions of the trade...The rifle was made by Gibbs of Bristol. The weight was 21 lbs., length of barrel 36 inches , weight of spherical belted bullet 3 ounces {so about a 5.3 bore} , of conical bullet 4 ounces, charge of powder 16 drams {one ounce or 437.5 grains!} . The twist was one full turn in the length of barrel. The rifling was an exceedingly deep and broad groove (two grooves), which reduced the difficulty of loading to a minimum...It will be observed that the powder charge was one-third the weight of the projectile, and not only a tremendous crushing power, but an extraordinary penetration was obtained, never equalled by any rifle that I have since possessed". Even given this propensity for large powder charges, it does seem like he was willing to balance bullet weight and powder charge a bit when he writes in In the Heart of Africa , "...but as I rushed toward him with a shout, he turned toward the jungle, and I immediately fired a steady shot at the shoulder with the 'Baby.' As usual, the fearful recoil of the rifle, with a half-pound shell and twelve drams of powder... {328.13 grains}" . He notes in this book that he also fired "Baby" with 10 drams of powder. Of course, it is important to note that while "Baby" is often referred to as a 2 bore because of the "half pound shell" reference, the "shell" was a conical so it seems to me that "baby" was almost certainly a 4-bore.
Now, all this provides an interesting contrast to our earlier discussion. Remember that the cartridge guns we were talking about all had curiously shorter barrels. I do wonder if the high dollar makers were willing to sacrifice a bit of performance for a more balanced feel when adding a second bbl in the case of doubles but I can't really imagine them willingly making such a sacrifice on a single bbl gun when moving to cartridges. The only logical conclusion, therefore is that Baker was requesting the extra length in his front stuffers to accomodate his much higher powder charges. 400+ grains was probably not his standard load but he clearly liked the idea of being able to burn all of that powder now and again. I imagine when one makes a habit of following wounded elephant with a front-stuffer, one gets pretty immune to recoil and wants all the punch possible. Interestingly, he recalls in one book having fired that weapon only under 20 times in a number of years and never failing to bag the target when needing to resort to such extreme measures.
Best,
John
