Muzzleloader Roundball BC's?

[Chopaka81]

Looking for the Ballistic Coeffients for round balls for the common calibers of 45, 50, & 54.
Thanks! Don

 

[J E Custom]

Sorry but they have to be '' TERRIBLE''

i'M not sure there is a bc for them.

I would be interested in hearing if there is.

To calculate BC you need weight,length,diameter,shape,drag and other
information ,And with a round ball all you have is weight and diameter.

J E CUSTOM

 

[edge]

IIRC a 50 caliber RB weighs about 177 grains and has a BC just under 0.10

I don't know the others, but I bet that Google does

edge.

 

[Buffalobob]

Ballistic Coefficient In order to calculate the trajectory of a bullet in flight, its ability to push aside the air and retain energy must be known. This property is known as the bullet's Ballistic Coefficient (BC). To calculate an accurate BC for any given bullet requires actually shooting it many times at various velocities, and measuring it's change in velocity over range. There is a simple way to approximate the BC for a roundball, though, so we can play around with theoretical trajectories.

For a roundball traveling more than 1300 fps:

B.C. = Ball Wt. in grains divided by (10640 x ball dia. x ball dia.)

Example: For a .535 ball weighing 230 grains, 230 divided by (10640 x .535 x .535) = a BC of .0755. Lyman's Black Powder Handbook gives a BC of .075 for a .535 in. ball, so the agreement is good. This formula courtesy of "Lee in Denver"

No guarantee as to its validity but given the BC for a 22 rimfire bullet it seeems about right.

 

[Chopaka81]

Buffalobob,

I did a search using google and came up with the same web site. I loaded the formula into an EXCEL spreadsheet and came up with some pretty low BC's.

To bad ExBal will not except a BC below 0.1. Found that out after I posted this question.

The muzzleloader group at my gun club is complaining about having to shoot down a slight grade for our 50m berm as compared to the 100m berm. They want to shoot on perfectly level ground.

I'm thinking that a 10 to 15 degree slope is not that big of a deal, looks like it might amount to a little over an inch - if that. Given that they are using iron sites, I just do not see it having that dramantic of an influence on the ballistic curve. I think it is more of a head game than anything else.

Thanks for the bandwidth... Don