With a twist rate of 1:65 that spells Minnie ball to me,
Really? Sounds more like a round ball twist to me. I guess the Colt was at 1:72, though. I guess nothing is definite. Go figure.
John
I was kind'a wondering about that too John,.... but, I've never played around with the Civil War era muskets, so I know nuthin' about'em.
Here is my take on this....and this is strictly my own thinking, based on a somewhat limited experience since I've never belonged to NSSA, and that's the folks who can do a much better job of explaining this than I can.
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.
The Minnie, as a rule, is almost twice the length of the diameter which puts the majority of the weight at the front one-half of the bullet.
This resistance, from an object at rest, at initial ignition, puts strain on the "skirt" surrounding the hollow base, and, if the twist rate is too fast at the instant of "engraving", you will get gas cutting or blow-by at the skirt which in turn affects the accuracy tremendously.
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.
That is the very reason I use a lead alloy, with a wee bit higher bhn, rather that pure lead which is highly recommended for any Minnie, in most every case, and I choose a very thick skirt which is found on the Parker Hale type casting Moulds.
This, in turn, also allows me to use a little more powder without fear of blowing the skirt of the hollow base Minnie and loosing accuracy.
Can you shoot a Minnie in a .54 or .50cal? Absolutely!
But...you will have to reduce your powder significantly to get any semblance of accuracy.
Here is a very short fer-instance;
With my "hunting load" in my .58 Colt, and using a wee bit higher bhn in my casting, my typical load is 100gr FFg Goex.
If I were to simply "punch paper" all day I would use 40 to 43gr (half-way between 40 & 45) of FFFg Goex, (that is 3F vs 2F) and pure soft lead in my casting.
If I never expect taking a shot longer than 50 or so yards, while hunting, I would use 70gr FFG and pure soft lead for my casting.
Did any of this rambling make sense?
Still clear as mud?
Hopefully someone will come along shortly and fill in all the blank spots I have left, although I am quite sure of what I want to say, I am not all that sure it came out that way.
Uncle Russ...
Topic: Chiappa 1858 Enfield. (Read 2714 times)