John- you are spot-on with that last statement about experiments or reasoning gone wrong. Such was the case in Merry Old England in the 1800's. An example of this comes in a quote from Forsythe's little book, page 54.
" The twist varied from a turn in 3ft. to a turn in 4 1/2 ft. of barrel, and, as may be imagined, the charge it would admit of, retaining it's accuracy as a rifle, was ridiculously disproportionate to the weight of the ball. It cannot be denied that considerable accuracy of flight was attainable with this rifle, with small charges and great elevation, and at standing(animal) shots of course, considerable execution might be done by a perfect judge of distance, when time was allowed for the necessary calculations; but the effect of the ball, so used, was very insignificant on the large and powerful beasts of chase. If a large charge of powder was employed to give greater power, "stripping" was the result folowed of course, by great inaccuracy of flight - reducing the rifle, in fact, to an imperfect smoothbore. Well, to remedy this, some long-headed individual introduced the two-grooved rifle, with a belted ball. A greater hold on the grooves as thus obtained, and a larger charge of powder could be employed, retaining the advantage of the rifle principle; but, instead of leaving the rate of spiral in the grooves as it was, in which case some small advantage might have been obtained, it was increased till it ran as high as a whole turn in 2ft. of barrel!
