1/60 twist would be slightly better....
A "chunk Gun" usually is a percussion or flint lock rifle with a long, large diameter barrel that can be upwards of 2 or 3 inches across the flats. They usually have a tang and globe sight or possibly a scope such as a Unertl. Since they are heavy, even 40 or 50 pounds they are shot from a bench or on a log (chunk) with the shooter prone. In most cases they are hand made with the best hardware you can find such as Douglas XX barrels, Lewis locks and Lewis triggers and Unertl scopes. Because of the rules most have conventional side ignition systems and not an under hammer.
Do a Google search for the match named after "Alvin York" or the "Bevel Brothers" and you can see what the guns look like.
John
I have a 54 T/C Scout with 1/20 twist. It shot RBs with light loads well at 25y but I never have taken in back farther yet to see how it does.
Aim small, miss small!
It would be worse, and I think it is true that 1:60 or slower would be better than the quite passable 1:48.
A conventionally patched round ball, with wrinkles round the edge, is bound to be less concentric with the bore axis than a good cylindro-conical bullet, grooved or paper patched. Eccentricity of mass affects accuracy in two ways. It could induce a wobble or corkscrew motion in flight. but that isn't much of a problem with round ball. It also produces an angular deflection at the muzzle, and this is proportional to the speed of rotation. The best twist is the slowest that will keep the front of the ball at the front.
That "quite passable" 1:48 twist still has limitations (with roundball) that the 1:66 does not - that said - 1:48 is a good compromise if the shooter sees a need to experiment with minies or other elongated missiles -----going the other way some slow twist barrels (1:72 etc) seem to need a substantial load to get them to shoot acurately.
Bob
Tin in roundball is a poinless excercise - dont need it!!
1) Tin is a much more expensive metal than lead - save your money even if you already paid
2) softer is better for roundball
3) I get your castability argument for making boolits - but it has minimal effect casting roundball - roundball is easy!
BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
BR | Bench Rest | M | Magnum | RN | Round Nose |
BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
GC | Gas Check |