Forsyth's Rifle Design

"I have found that a 14 guage barrel rifled at the rate of 1 turn in 8 ft. 8 in., if correctly made, will throw a plain spherical bal with sufficient accuracy for all practical purposes up to 200 or 250 yards, and if a range of 150 yards only is required, the same accuracy will be obtainable by a turn in 12 ft. A rifle on this principle requires the grouves to be cut very shallow and broad, and the lands very narrow, almost knife-edged; the ball should just touch the lands, and no more, and the hold on the grooves is given by a very substancial patch; the loading, if the ball is properly fitted, is most easy, and no rifle that I am aquainted with fouls so little. The ball will never strip whatever charge you use, with so little twsit in the grouves; and balls of any degree of hardness may be used."
: "The heights of its trajectory (a 14 guage)were at 25yards, 1 in.; at 50 yards, 2 1/8 in.; at 75yards, 2 3/8in., on the line at 100. the points blank of this rifle with 3 drachms(drams) is about 60 yards; with 4 drachms (drams), about 85yards; with 5 drachms(drams)100yards. The only effect fo increasing the charge was o lessen the elevation, and make the rifle shoot more accurately, as well as hit harder; the resoil, of course, incresed in proportion."
: These quotes will take some understanding and probably re-reading.(did for me) The key to these ballistics, is the very shallow rifling, in effect, I would estimate at no more than .004" -no more! The more depth there is, the more irregular the surface of the bullet upon discharge, the more atmospheric drag thereis, therefore necessitating faster twist for stability, therefore deeper rifling to prevent striping, therefore more damage, therefore faster twist, therefore deeper needed, therefore, etc, etc.
: I do wonder if a present company would make such a set of barrels, or even one, 14 guage, 26 inches long, 1/4 turn in the rifling would be perfect. Les Bauska made such a set for a friend of mine, many years ago, but I've lost touch with Dave over 2 decades & I wonder if he ever made his double rifle on Forsyth's principles? What a smasher of Moose, it would be.
Daryl

 

[Deadeye]

Are you familiar with the rifles marketed by October Country? Large bore and said to be made according to Forsyth's principles.

 

Not really, I remember seeing a .69 rifle English rifle for sale somewhere, and that name sounds familiar. If indeed, it has a very slow twist and SHALLOW rilfing, it will work just fine. A twist at or over one in 100" probably won't give one hole accuracy at 100 yds. with standard RB depth rifling, in the .010" to .012" deep. Although my Green River barrel was only 1 in 66", it still shot well with heavy charges, probably due to the .012" rifling. Less depth at that rapid twist woundn't do so well, I certain. It would strip.
: Like Forsyth says, the faster the twist, the deeper the grooves needed to hold, so the more damaged the ball becomes therefore nesessitating faster twist to resist atmospheric stability problems.
: It does seem to me their rifle had a very slow twist. The really neat thing is the more powder your put in, the better they shoot, instead of the opposite. My rifle wasn't true to Forsyth's plan, but the combination sure worked well with 1 1/2" groups at 100yds. time after time, paper patched balls or cloth, pure lead or WW; It really didn't matter.
Daryl

 

[Deadeye]

I have their catalog, I'll check tomorrow and see what their twist was, seems like it was about 100.