I have often wondered why the twists were so fast. Before 1800 Baker had shown the British that slow twists shot accurately. But the British and others on the Continent I am sure, for the most part stubbornly clung to the fast twist.
The fast rifling twist and the multi-leaf sights kinda go together.
Many English rifles with fast twists using very light for the bore size powder charges had sights with leaves for 50 and 100 yards then perhaps another for 150. The typical American rifle needed only one sight for all three ranges with a little hold over at 150.
I think that the fast twist barrel was the result of using shotgun like powder charges and the resultant shotgun like velocities in rifles. The low velocities needed more twist for acccuracy and the fast twists WERE accurate if this is the only criteria.
It takes substantially more powder to get a one ounce ball to 1600 fps than it does to move a 1 ounce charge of shot at 1250-1300. My 16 bore rifle needs 5 drams or more to make 1600. Why 1600? Because 1600+- gives a flat trajectory and good short range power for a "stopper". BUT this is dependent on the conditions under which the rifle is used. If used at ranges no more than 50 then much lower charges could be used for game like deer. So we are back the to European rifle with its fast twist and presumably light powder charges used for short range shooting at game. A load in the 16 bore (.662 ball) rifle that makes 1100 fps or so will kill as well at 20-30 yards as a 150 grain load will at 100 since the velocity at impact is not that much different. But the 1100 fps load will be impossible to zero past about 50 yards for the reasons in the following quote from "The Sporting Rifle and its Projectiles" by Forsythe.
While a turn in the barrel will give excellent accuracy in the bigger ball sizes it will limit velocity, so the 50 and 100 yard leaves. This according to Forsythe, who BTW thought the fast twists were idiotic, and I believe was the reason the belted ball was invented with its 2 groove barrel. A large caliber ball could be over twisted and still use a heavy powder charge with some success. Forsythe's ideas on slow twists were surely influenced by Johnson's "Sportsmans Cyclopaedia" 1831 which he references. But he also had personal experience:
"...I once possessed, 13 bore, with a turn in 3ft 6 in., invariably stripped if I gave it the least thing more than 1 3/4 drams:---with that charge is shot splendidly, but the elevation was excessive, the rise is its 100 yards trajectory being about 11", rendering it utterly useless and absurd for sporting purposes, that is, for shooting game in the field."
In this case with this twist, 1:42, I have to wonder if a larger ball or heavier patch (tighter fit) might have been tried to allow a heavier charge of powder but he does not elaborate. The rifling FORM would be on interest too.
It was impossible to make a fast twist heavy game rifle with a short barrel and a 26" (for example) twist. The patch will blow. As a result a lot of Elephant and such were shot with smoothbores. I don't know at what caliber the one turn in the short barrel becomes a serious detriment to the velocity obtainable. It would require financial outlay I cannot afford to find out. But if someone wants to have a 12 bore barrel cut with a 26" twist for testing I would really like to see the results.
The American rifle, with its longer barrel, and perhaps the longer barreled European rifles, may have had a slower twist since an American rifle with a "4 ft barrel" would have about a 4 ft twist based on the "one turn in the barrel" formula.
This is very good twist for RB rifles up to 54 caliber at least.
But what about rifles with barrels OVER 48"? There are some out there. Did they make a rifling guide with a 5 ft cylinder and one turn in its length and use this for everything? A 48" cylinder would be good for barrels to just under 48". So to make a 48" barrel the cylinder would have to be longer and its seems to me that it would be easier to lay out one turn in the length than 2 turns or 3/4 turn. But I have never tried it so I am guessing. So if the guide would rifle barrels to 50 inches would it have a 1:55 twist?
Did the European guild system rifles have barrels that were completely finished when they arrived at the gunstocker? A dedicated barrel shop would have room for extra guides not being cluttered up with all those stockmaking tools.
So did the barrel maker have a selection of guides to accommodate the various lengths or did they have something like a sine bar that could be adjusted?
The European rifle used a heavy ball and a short barrel, usually at short range it would seem. Low velocity makes shots on game past 50-75 yards an exercise in range estimation. The higher velocity American or rifle with is generally smaller ball, longer barrel, slower twist and higher velocity made hits on game a "aim for the middle and press the trigger exercise to 120 yards or so. This also true of larger bored rifles such as Forsythe used. This can be extended to 150 plus on vertical targets like people.
So from the twists used it would seem that the Europeans, in general, shot at close range, at least at game and used relatively light charges that with the larger balls gave adequate killing power.
Dan
