The 1-48" twist story dates back to the 60's when Navy Arms and others first imported the Zouave Rifled Muskets. They had a 1-48" twist, 6 lands & grooves (actually, 3 of each) only .003" deep. This is the proper set-up for Minie type projectiles. We soon found out that patched balls didn't work well with such shallow rifling, especially with more than 40 to 50 grains of powder. It now appears that the patching slipped across the rifling at higher speed since it had difficulty gripping shallow grooves, at least that's the thinking.
It really had nothing to do with the actual twist rate since a couple guys named Hawkens from St. Louis did pretty well with the same twist rate. The difference was that they used cut rifling, .010" inch deep with twice the lands and grooves. Problem is that type rifling depth doesn't work well with Minie or Maxi type projectiles, they need shallower and much wider grooves. There's also a difference between cut rifling and button (pressed) rifling, found in many modern guns from overseas. Although button rifling with multiple grooves and lands works adequately, it's not as long lasting as cut rifling. It took a fair amount of time and powder to figure some of this out.
A few things did become clear about faster rifling twist though. Patched balls can be fired from fast twist barrels but not at higher velocity. Smaller bores work much better than about .45 and up. The best example is TC's use of 1-30" twist in the .30 and .36 caliber Cherokee & Seneca rifles. The little .30 will shoot all day with 10 grains of FFFg at about the same velocity as a .22LR. That's 700 shots from a pound of powder. Most any rifle can shoot most any projectile, but you have to match rifling type with projectile speed. Somewhat simplified, but this is what it amounts to. Patched balls with more and deeper grooves, elongated projectiles with less and shallower grooves. :hmm:
