Interesting ballistics - The HuntingPA.com Outdoor Community
 
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post #1 of 9 (permalink) Old 11-05-2011, 11:37 AM Thread Starter
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Interesting ballistics

Figures are from the Lyman Black Powder Handbook 1st ed.

peak pressure for 60 grains in a 45 caliber barrel
in Lead units of pressure
28 inch, 5,660 LUP
40 inch 9,140 LUP
43 inch 9,720 LUP


substantially more peak pressure in longer barrels. Even with such a moderate load, peak pressure increases between the 40 inch and 43 inch bores.

compare the figures for the same charge in a 54 caliber barrel

28 inch 4,860 LUP
34 inch 6,800 LUP
43 inch 7,000 LUP

the same trend is apparent.

I would have thought the Pressure in the 54 would have been higher because of the much heavier ball. I also never expected the pressures in a 45 to be so high with a moderate load like that.

Just thinking out loud, but it seems like heavy loads would be more dangerous in a longer barrel than a short barrel. Not that I would ever push that limit anyway.

An interesting thing is that pressures drop between 45 cal and 54 caliber. Considering the larger heavier ball, I would have thought the opposite.
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post #2 of 9 (permalink) Old 11-05-2011, 11:54 AM
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Re: Interesting ballistics

Interesting findings for sure. Thanks for sharing.

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post #3 of 9 (permalink) Old 11-05-2011, 03:47 PM
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Re: Interesting ballistics

Maybe the difference in pressure between 45 and 54 has to do with bore volume, like a hose nozzle when you make a restricted stream that really washes off your driveway compared to no nozzle at all. By the way 60 grains of what granulation of powder was making these pressures and what weight and kind of projectile? Thanks for the info, John
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post #4 of 9 (permalink) Old 11-05-2011, 03:55 PM
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Re: Interesting ballistics

9700 LUP sounds like alot but is it really? What does it mean to someone who has learned to live with PSI? Are any of those figures anywhere close to dangerous levels? I've only heard of LUP once in 20 years in an article by Sam Fadala........John
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post #5 of 9 (permalink) Old 11-05-2011, 09:06 PM Thread Starter
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Re: Interesting ballistics

It was fffg Goex and patched round balls.
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post #6 of 9 (permalink) Old 11-06-2011, 01:18 AM
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Re: Interesting ballistics

Looking at the balistic charts in the Lyman handbook I have noticed that the muzzle energy produced per grain of powder goes up substantialy according to bore diameter. It seems to peak around .54.

50 grains in a .54 makes more energy [foot pounds] than say 50 grains in a .45.
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post #7 of 9 (permalink) Old 11-06-2011, 10:43 AM Thread Starter
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Re: Interesting ballistics

Yes, and with far less bore pressure
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post #8 of 9 (permalink) Old 11-11-2011, 02:11 PM
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Re: Interesting ballistics

Smaller bores have more pressure and more pressure does not mean more velocity. Most muzzleloader barrels cannot burn more than 120 grains of powder and still be under the max. pressure limits.
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post #9 of 9 (permalink) Old 11-13-2011, 11:46 AM
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Re: Interesting ballistics

I am new to muzzle loading but not to explosives. I am an explosives expert for the US Gov. Since black powder and even smokeless powders do not explode (The burn very fast) What you are seeing is the fact the smaller bore rifle is providing less room for the gas from the burning to expand while the larger barrel give more room for expansion during the burning process. Since gun powders burn not explode the longer barrel gives more time for the powder to burn thus allowing more of the powder to burn in the barrel and more pressure to build up. Just like a modern day rifle for long distance shooting will have a 24- 26 inch or longer barrel. You are simply giving the pressure more time to build and ensuring all powder is burned before leaving the barrel. The longer barrel is a two fold effect, more time more pressure, more efficent burn of powder.

The reason the .54 is making more foot pounds of energy is not because of the powder it would have to be do to the size and wieght of the projectile.

I have not seen the Lyman book but I think the best way to explain it is using two examples. The garden hose was a great example. The more you restrict something the more pressure it will build up. The other is throwing a rock. If you throw a small rock say about the size of a marble it will go fast and hit pretty hard. On the other hand if you throw a rock the size of a golf ball it won't go as fast but will do more damage when it gets there.

I hope this helps.

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