How much will that horn hold?

[trentOH]

If I'm holding/looking at a horn, one of my questions will be "How much powder does it hold?". You see, I like to shoot my Brown Bess, but she can really eat a bunch of powder! Is there a formula or another reliable way to judge about how much powder it will hold, short of filling it with a substance  and measuring how much comes back out?

[Elnathan]

I'd measure the length to the end of the internal cavity from the plug (measure the inside of the curve and the outside of the curve, add the two together, and then half to get an average), then use that length plus the dimensions of the plug to find the volume, treating it as a cone ( Vcone = 1/3 × pi × r2 × h). That would probably get you close.

Or, you could just fill it up and measure it out again, as you said. That would simpler and more accurate....

[smylee grouch]

Or you could start with one lb. , fill the horn and weigh whats left of the one pound. 

[rich pierce]

I've got a horn that will swallow about a pound and a half. Love it.

[Tim Crosby]

 Sometimes, especially with small horns people will ask how much will it hold, rather than weight I go by loads,  so I fill them with Salt. Then take a measure set at 50grs and measure out how many loads I would get. No weight involved but it will give you an idea of how many shots you will get. 50 is ball park, the total can then be divided by the actual grns, loaded and you will know how many shots you will get out of a horn, once again not exact but close. Just remember if you prime from your main horn that will cut down on the number of shots but not much.
 
  Tim C.

[trentOH]

OK. Once I calculate the volume of a horn in cubic inches, I need to know how many grains of powder in a cubic inch. Does anyone have answer to that little mystery of the universe? Thanks!

[oldtravler61]

   Trent don't have the answer. But if you need a lot of horn to hold powder. Go whack a longhorn steer or Australian water buffalo. Now they got horns.
  But on the serious side. A large bison horn should do the trick or cattle horn in simular size should work.
 How much weight do you want hanging off the side of your neck?
  A pound of powder goes along way even with a Bess.....jm2c...Oldtravler

[trentOH]

Australian water buffalo season isn't open yet in Ohio, but that's a fine idea. I sometimes see longhorns mounted together at flea markets, but I don't need to have other shooters envious of me at Woods Walk.

Twenty shots is just less than I'd like to be able to have on me. 35 shots at 100 grains is half a pound of powder. The real weight would be 35 round ball.

[Tim Crosby]

  See if this helps.

  Tim C.

http://chuckhawks.com/blackpowder_volumetric.htm

[oldtravler61]

  Tim very interesting article. My chronograph  shows a vast difference in velocity, also depending on powder choice and brand. Thank you for the article.  Oldtravler

[wmrike]

Cubic inches to grains is awkward - one is volume and the other is mass.  The cubic inch calculation for a horn is approximate at best, and the powder can vary in density depending on its blend and granulation.  I just fill the horn, empty it, weigh the powder, get an exact answer, and walk away.