.54 Sharps Ballistics

[johnefelts]

Does anyone have ballistic coefficient info or a calculater for the sharps .54 ringtail at 525gr. Probably silly but I cant sleep until I figure this out.;)

[kevikens]

I'm surprised nobody made a stab at this one so let me try. What I am offering is extrapolation from the .58 Minie to the Sharps. According to Lyman's 1974 black powder loading book the standard Minie has a 505 gr minie coming out of the barrel, 32 inches, at just over 700fps with a muzzle energy of just over 500 ft. lbs. (just over 400 ft lbs at 100 yards). Lyman gives it a ballistic coefficient of .145. From a contributor of the Muzzle Loading Forum (Civil War Ballistics, 200 the author gives a ballistic coefficient of .160 for the Minie ball. Both of these are with a standard 60 grain 2fg black powder load. This is pretty close to a Sharps 525 grain ring tail as it too uses about 60 grains of powder and bullet shape is similar. I would guess that in the carbine version the muzzle velocity is about 75 fps slower but in the rifle version is pretty close to Lyman's figures. The Black Powder Handbook by Sam Fadala, about 1990, gives a .45 Minie ball of 265 grains a ballistic coeefficiency of .156. The actual formula for ballistic co-efficiency is the ratio of a bullets weight (in grains) to the product of the square of its diameter plus a somewhat subjective "form" (round, conical, spitzer) factor. Thus 525 times .2916 ( the square of .54) is .153, which is pretty decent. Since the ring tail is not a round ball which reduces the co-efficiency, nor a spitzer which would increase it (by reducing drag) but a conical which subjectively we will say does not adversely affect its speed and drag, I would extrapolate here to say that firing a 525 grain ring tail with a 60 grain charge from a sharps carbine barrel will give a bullet with a co-efficiency of .153  about 650 ft per second muzzle velocity, about 470 ft lbs at the muzzle (plus a rainbow trajectory). The black powder hunting loads in the books have higher loads, say 90 grains in a .54 Plains Rifle, but while that flattens the trajectory with a muzzle velocity over 1000 ft/sec it does not alter the ballistic co-efficiency of what the projectile is. That remains a factor of weight, form and diameter. I hope that I have this correct and if not I hope someone can explain it in a more lucid manner. Feel free to point out any errors. I won't be upset and would appreciate knowing more about Sharps ballistics.

[Southron Sr.]

the rebated base of the Sharps X-Mas Tree Bullet had something of a "Boat-Tail Effect."

[kevikens]

It may to some extent. I didn't mention the boat tail effect, a "form" enhancing ballistic co-efficiency, as I did not think of ring tail possibly having a boat tail effect. Does anyone know if any bullet had the true boat tail design circa 1860's?

[johnefelts]

It may to some extent. I didn't mention the boat tail effect, a "form" enhancing ballistic co-efficiency, as I did not think of ring tail possibly having a boat tail effect. Does anyone know if any bullet had the true boat tail design circa 1860's?

I found last night a BC calculator that took this very thing into consideration,and after adding my Bullets info,IE the weight the Caliber and a few more numbers the Calculator gave me a BC 0f .225 which is close to the .153 you had mentioned before,I think the ringtail must cause less drag on the back of the bullet,oh by the way Im sendin your bullets out Friday.

[kevikens]

John: the sharps bullets came today. Thank you very much for your generous gift. There will be something in the mail shortly to repay your kindness, though you may have a difficult time redeeming it.