...... It seems, from my reading and on some of my own doings, that anything faster than about 1:62 destroys the integrity of the "skirt" or hollow cavity on a Minnie at the exact instant of bump-up, or obturation........
.....This principal is likely the very reason "Progressive, or Gain Twist Rifling" came into being.
During bump-up and at engraving, the rifling is slow, then getting a wee bit faster toward the muzzle to better help stabilize the long hollow base projectile without blowing the skirt as the projectile exists the barrel...the projectile becomes more gyroscopically balanced, if you will..........
The Pattern 1853 Enfield (commonly referred to as the three-band Enfield) had 1 in 78" pitch three groove rifling and 39" barrel. The P.56 Short Rifle with its 33" barrel had the same rifling. The short rifles are often referred to as two-band Enfields.
The P.58 Enfield (Naval Rifle) had a heavier 33" barrel then the P.56 and 1 in 48" five groove rifling. Subsequent Short Rifles, the P.60 & P.61, each had the same barrel weight and rifling as the P.58. The Chiappa rifle with 3 groove 1 in 65 rifling is not a copy any particular Pattern Enfield.
The five groove heavy barreled short rifles have a reputation for good accuracy, and this may also be because the rear sight was further from the eye than on the P.53, giving for some a better sight picture. I've seen both shoot well and here in the UK where we have competition out to 600 yards (sometimes 800 yards). In the 19th Century Rifle Volunteers shooting in Regimental competitions or at the NRA(GB) annual rifle meetings in the 1860s also used them out to 600 yards (generally the P.53, which was their arm of issue).
There's confusion about the term progressive rifling. This is different from gain twist, which as is noted starts with a slow rate of twist (or even straight) then increases in pitch.
The Enfields had progressive depth rifling; ie. the groove depth got shallower towards the muzzle (the bore remaining unchanged). This helped reduce fouling. For the short rifles the grooves were 0.013" deep at the breech and 0.005" deep at the muzzle.
If you're interested in shooting Enfields have a look at the
Military Muzzle Loading Rifles section of my web site.
David