.451 Whitworth ballistics

[John Gross]

I asked this question at another forum, and the esteemed Tony Beck gave me his thoughts on it. With no disrespect to Tony, I told him that I was going to continue to gather as many opinions as I could. So, if anybody would like to offer their thoughts, here is my question.

For research purposes I need the downrange ballistics, out to 1,800 yards, for the .451 British Whitworth muzzle loading rifle. Such things as retained velocity, bullet drop, wind deflection, time of flight, etc. I'm even willing to purchase a ballistic program IF IT WILL WORK. Some of the programs (such as Sierra Bullets) says it is not compatable for black powder. I don't know why and I'm waiting to hear back from them about this. It would seem to me that a 45 caliber bullet of a certain shape, length, weight and traveling at 1,300 fps from the muzzle would have the same downrange performance no matter the propellent.

Anyway, here's my Plan B and my specific question. Since a 45-70 500/550 grain bullet is very close to the .445" diameter 530 grain Whitworth bullet, and they travel at very near the same muzzle velocity, does anyone see any reason why I could not use the 45-70 ballistics to get a close approximation on how the Whitworth would perform? The reason being that 45-70 ballistics should be easy to find or calculate with a ballistic program.

While I appreciate any advice, this is for a serious research project, so if you are just taking a "wild guess" please say so and I will weigh your information accordingly.

Thank you,

John Gross

[Jim Brady Knap's Battery]

Basicly it would seem to me that the end result is a component of weight and velocity. What is doing the pushing or what it is being pushed from shouldn't make any difference. I guess bullet design and the areodynamics of a given projectile should be considered also.

Jim Brady
2249V
Knap's Battery

[John Gross]

Jim,

Thank you for your reply. Yes, you are correct that I need to be sure to compare apples to apples. For example, Lee makes a 500 grain spitzer for the 45-70 with a rather high (for black powder arms) ballistic coefficient of .443

It would be unrealistic to compare this to a round nose Whitworth bullet with a BC of about .375

John Gross

[dbm]

John,

Have a look at the article on '.45-70 at Two Miles' in the 'Long Range Rifle Fire' section of my www.researchpress.co.uk web site. There may be some ballistic information of use to you there. Although firing a .45 cal projectile the bullets used are lighter then Whitworth's so the usefulness of the information to your project may be limited.

The War Office 'Enfield and Whitworth Committee' report of 1861 includes some information that may be of use. The average mean angle at several ranges is below.

500 yards    Angle 1d 31' 20"
800 yards    Angle 2d 34' 00"
1100 yards   Angle 3d 42' 00"
1400 yards   Angle 4d 27' 30"
1700 yards   Angle 6d 29' 00"
2000 yards   Angle 7d 18' 00"

Charge at 500, 800 & 1100 yards was 2.5 drs. of Curtis & Harvey No.6. At 1400 & 1700 yards the charge was 70 grs. and at 2000 yards 85 grs. of the same powder. Bullet at all ranges except 2000 yards was lead cylindrical. At 2000 yards a hexagonal bullet of 6 lead and 1 tin allow was used. These tests were undertaken in 1857.

The 'Committee on Small Bore Rifles' reporting in 1863 have similar results for Whitworth with different weight barrels. The later (1867) report on 'Army (Whitworth) Rifles' has reports back from various troop trials, but there's little ballistic information contained therein.

David