ROT Smith Hoyt reline

[fullertc]

I'm reading a 1/3 turn in a 22" bbl which should put me a t 1:66 twist. Am I wrong? Using the Greenhill formula, that may be a little too long. What are your measurements? I'm trying the T/C Maxi ball sized to .515. What loads with what twists are you shooting? Thanks.

[Gary Vikar]

That's is Hoyt normal twist for his Barrels. Bobby told me that this rate was the best for a skirmisher as you could pretty well shoot any bullet in it. I found the the hodgdon Bullet (North-South skirmish bullet) works the best using 42 grain of 2f or 3F. Midway has the mold in stock https://www.midwayusa.com/product/1010242234?pid=637400

[fullertc]

Thank you, Gary, but how do you get 42 gr of powder in a Smith tube? Typo? I ran a tight patch from the muzzle of my Smith Hoyt relined 22" bbl and it turned 1/3 as it exited the breech. I multiplied it by 3 to get 1:66". The bullet moulds that I have are outside of the "specs" according to Greenhill, give or take some?

[sfoster]

The mold in his link is for a .578" minie. Perhaps so is the load.

[Gary Vikar]

Thank you, Gary, but how do you get 42 gr of powder in a Smith tube? Typo? I ran a tight patch from the muzzle of my Smith Hoyt relined 22" bbl and it turned 1/3 as it exited the breech. I multiplied it by 3 to get 1:66". The bullet moulds that I have are outside of the "specs" according to hill, give or take some?



I thought it was for a musket. 28 grains of 3f, a paper wad over the black powder. Next 7 grains of grits. I use a .515 bullet .50 cal Lyman mold. Also a Larry Romano Spencer bullet. The bullet is one of Larry prototype with excellent results. Era Gone by was a new copy of the original C.W. smith that shoots well also. The lube I use is SPG. Also SPG a new lube for hot weather.

http://erasgonebullets.webstarts.com/smith_carbine_50_caliber.html

[R. McAuley 3014V]

You really depend on Greenhill's equation? You might want to read his 1908 treatise "Notes on Dynamics," which was used to describe the elliptical flight of lead-steel artillery projectiles, not lead-alloy bullets. Greenhill's work was mainly on elliptical functions, and was interested in their applications to dynamics, hydrodynamics, elasticity, and electrostatics.

Greenhill's "equation" negates friction caused by a projectile passing through the air; negates the earth's gravitational pull on the projectile; negates frictional forces of air acting counter to the rotation of the projectile; negates the inverse square law relative to gravity; assumes a terminal velocity of 2000 feet per second of a 6-inch ellipsoidal (egg-shaped) metallic shot that is 3.5 calibres in length, and a weight of 0.2 pounds (but of unknown mass density), then assumes the air density is 800 times the specific gravity of the metal. So if you want to base your new bullet design on "Greenhill's equation," good luck. There are other "equations" that have been attributed to Greenhill, but his equation relative to his Notes on Dynamics, was never intended as applicable to lead-alloy bullets. Greenhill taught in the Artillery College of the Royal Military Academy at Woolwich from 1876 to 1908.

[gemmer]

When Bobby relined my Erma Gallagher for the Smith/Maynard bullet I asked him to the same twist as a Smith with a .515 groove. I really don't know what the twist is, but it shoots the Lee Smith/Maynard from Lodgewood extremely well. It's a .518 mould and I size to .517. It's chambered for Gallagher cases.