Projectile

[DoktorD]

Just trying to figure out the general increase in weight of the projectile if you use a miniball style mould versus the traditional cannon ball.

Looking at the picture of GGaskill's mould I got a rough cross section looking like this:







I'm estimating his miniball weighs roughly 0.42 lbs (6.67 ounces) in lead and 0.25 lbs (3.93 ounces) in zinc?

GGaskill can you verify your weight?

If this is true, its not too much more than the cannon ball which according to the shot calculator would be 0.329 lbs lead and 0.194 lbs zinc.

I think I might have a winning design 

HOWEVER, one question I have after reading the responses in this thread is: what kind of windage should I be giving it to allow for the expansion of the rear into the rifling, but yet not accumulate too much additional pressure behind the projectile?

GGaskill -- does your miniball mould still use the 1/40th rule?

[Artilleryman]

HOWEVER, one question I have after reading the responses in this thread is: what kind of windage should I be giving it to allow for the expansion of the rear into the rifling, but yet not accumulate too much additional pressure behind the projectile?

You want to have as little windage as possible the still allows the projectile to slide down the barrel without hanging up.  You control your pressures by the amount of powder charge.  Of course you need enough pressure to cause the skirt of the projectile to engage the rifling.

[Frank46]

If I remember correctly the more or less standard charge in a 58 caliber musket is on the order of something like 58 grains of FFg powder. if the powder charge is too much then you blow the skirt and accuracy goes south. I just responded to a new post with the suggestion of something like the foster shotgun slug with pointed nose and no hollow base. FWIW Frank

[DoktorD]

Ok, thanks guys!

Anyhow, if anyone's interested, I made a little calculator to give rough dimensions on a miniball for a given barrel diameter. Figured while I had all the calculations down I might as well make it available for anyone else that comes along lookin for someplace to start.

Miniball weight/dimensions

I'll let ya know how it goes after I get a mold and fire some out

[guardsgunner]

DoktorD,
   your calculator comes up pretty close on my 1.5 projectile.

[DoktorD]

Good to know!

Not everyone's is going to be the same length with same shaped void/nose etc..

But I'm glad it's comin close to what people already have 

It'll at least give someone a weight and some dimensions to start with...

I'm going to modify it so you can select your own dimensions when I get back from my test tonight