Most fast twist shallow groove barrels are made for shooting long cylindro-conoidal bullets. Despite this fact, fast twist barrels will shoot round balls accurately. Early flintlock English rifled barrels were famous for their accuracy yet almost all were fast twist. Later, after the American Revolution, the English switched to slower twists, influenced by the Kentucky rifles that performed so well against them.
The English switched mostly because fast twist guns with round balls are much more finicky than are slow twist rifles. It’s been long known that barrels with slow twists of 1-66 and up seem to throw almost any well fitting load into the same group. Large variations in powder charge don’t seem to make much difference. All shoot well if any shoot well. This leaves the slow twist shooter with only the task of finding proper ball size and patch thickness without having to worry a whole lot about exact powder charge.
Somewhat the opposite is true with round balls in fast twist barrels. Powder charge is paramount. The powder charge required for accuracy in fast twist barrels is always smaller than in slow twist barrels. The range of accurate velocities is also much more limited.
For example, a charge of 30-50 grains Black Powder or Pyrodex equivalent in .45 caliber is about right in a fest twist barrel like Whites 1-20. Velocities are not high at these charge levels. (900-1200 FPS is all you will get.) but it will do well on bunnies or squirrels. And it makes an excellent target load. It doesn’t hardly kick and recoil is low enough that you can shoot it all day long and not be bothered.
In 50 caliber, charges of 50-70 grains Black Powder or Pyrodex equivalent seem to be OK. Same principles apply to velocities and uses. The .50 caliber ball is heavier than the .45, 180 gr. vs. 130 gr. respectively, so it could be used for slightly larger game. Still, velocities are low enough that range will be limited. Remember that a round ball slows at 100 yards to about 50-60% of its muzzle velocity. This means that energy levels and thus killing power will be correspondingly low.
The powder charge required for accuracy
in fast twist barrels is always smaller
than in slow twist barrels. The range of
accurate velocities is also -more limited.
A .54 caliber ball will weigh in at close to 220 grains. 60-80 grains of Black Powder will produce an accurate load fully equivalent to many high power pistol loads . This is also true of the other smaller calibers. Don’t be fooled when they are referred to as low power loads. They can be just as powerful as many high power pistol loads and are plenty potent at close range.
Now let’s consider ball and patch size. Most fast twist guns have shallower grooves than are usually seen with slow twist rifles primarily meant to shoot round balls. White SuperSlug barreled rifles have rifling 3.5 thousandths deep, which is quite shallow when compared to White’s Green River round ball barrels with rifling 12 thousanths deep.
One of the advantages of the deep grooved slow twist round ball barrel is that you can use a relatively thick patch, say 25 thousandths, and a relatively small ball, say 10 thousandths smaller than bore diameter. This combination lets you load swiftly, using just the ramrod if you properly cone the muzzle as the old timers did.
On the other hand, fast twist barrels demand a relatively larger ball, no more than 5 thou smaller than bore diameter, plus a thinner patch. The goal is to get about a 10 thousandths interference fit between ball, patch and bore.
For example, a .45 caliber White fast twist barrel with .451 land to land diameter usually shoots well with a .445 caliber ball and a 15 thou thickness patch. This combination is a tight fit, much tighter than the .440 diameter ball and 25 thou thick patch you might use in a .450 caliber deep grooved slow twist rifle.
You will need as short starter to get the ball into the barrel and firm pressure on the ramrod to get the bullet seated on the powder. Nevertheless, it is a good load and will be accurate with 30-50 grains powder. I’ve seen many a bunny bite the dust with this or similar loads. If the angle is right on sunshiny days, you can see the ball fly, but it hits with enough force to take the bunnies head right off.
-fast twist barrels demand a-larger ball,
(about) 5 thou smaller than bore diameter,
plus a thinner patch. The goal is-a 10
thousandths interference fit between ball,
patch and bore.
White fast twist 50 caliber barrels measure .504 land to land. It’s best to use the commonly available .495 ball with a 20 thou patch. If you hand cast your balls, try a .498-.500 caliber ball with 15 thou patch. Patches are available in 10, 15, 20, and 25 thou thicknesses in most good muzzleloading stores. Ox Yoke makes good ones. Or you can purchase the cloth in a fabric shop. Take your caliper for measuring thickness and buy material made of pure cotton without any synthetics in it. Pillow ticking is best.
Most 54 caliber rifles measure very close to .540 land to land. This is true of White rifles. Use a .535 ball and 15 thou patch for an accurate combination.
The trick, as always, is to put the correct combination together. Personally, I can only do this by shooting a lot. There’s no substitute for it. It’s best to start low and gradually work the powder charge upwards in 5 gr. increments. You will eventually find a load that works. You’ll probably want to sight in to strike point of aim at 25-35 yards with open sights, simply because that’s the distance at which most small game is shot. You will find that groups will vary strikingly with increasing charges.
Despite this phenomenon, You can almost always find a good, accurate load. Once found, stick with it. There’s no point trying to get more power in what is essentially a small game/target load anyway. If you push too hard, eventually the powder charge will get large enough and the velocity high enough that the relatively shallow rifling will not hold the patch and ball and accuracy will go to hell.
A good example is the Pauley Sporting Rifle that I used in a match last year. You will remember that Pauley was the displaced Swiss who first invented the in-line action in 1812. I used a White G-series action with a White 504 caliber 1-24 twist shallow groove barrel to make a half-stock copy of what I thought a Pauley would look like, complete with false side-lock and false hammer. I had a photo of one so it wasn’t hard.
A little experimentation showed me that the 495 ball swedged by Speer was the best size. I worked up loads starting at 40 grains, finding the sweet spot at 55 grains of FFFg Goex black powder with a 12 thou pillow ticking spit patch. It would shoot all bullets into a ragged hole at 25 yards, double elbowed over the hood of my Suburban. The shoot was offhand at 25 and 50 yards and I managed to place well in the matches, against some exceedingly fine traditional shooters. To my surprise, the traditionalists weren’t at all taken back by the in-line Pauley rifle or the fact that I had built a copy.
Later, in the winter, the rifle proved to be a good choice for’ rabbits in the rocks’, as we call the game, once it was cold enough to get them out in the mid-mornings for a sunning session in the red rocks of this wide open country. Head shots didn’t ruin any meat either.
Don’t be afraid to use your White, or any other fast twist, shallow-groove rifle with round balls for target or small game. Be patient enough to work up a good load, limit your ranges and enjoy the fun.