Short barrel as powerful as long barrel?

[Powderandball]

Mike Beliveau has a film out on the YouTube’s describing the power of cap and ball barrel lengths.

In .44s, the standard size 8” barrels give about 270 ft lbs of energy. The same load in the popular (if inauthentic historically) 5.5” barrel “Sheriff” models reduce that down to just over 200 ft lbs.

However the really short 3” and under “snub nose” or “avenging angel” type guns out there, of which Pietta makes repros of, have abysmally low ballistics. Something like 60 ft lbs, about on par with a .25 Auto.

So below 5.5” the cap and balls guns plummet in velocity and energy, and for my personally I prefer the added power of an 8” barrel.

Take a look at this chart with velocity, charges and barrel length comparison. Black Powder Ballistics

A .451 ball loaded with 28 grains of pyrodex fired from a 5.5” barrel give 108 ft/lbs (146 joule)

A .457 ball loaded with 46 grains of pyrodex fired from a 5.5” barrel give 350 ft/lbs of energy (474 joule).

A .451 ball loaded with 28 grains of pyrodex fired from a 8” barrel give 113 ft/lbs (153 joule).

A .457 ball loaded with 35 grains of pyrodex fired from a 8” barrel give 242 ft/lbs (328 joule).

So in fact, the 5.5” barrel is more powerful than the 8” barrel when the powder charge is increased. Perhaps a 40 grain charge in the .44 3” Deringer actually made it more powerful? Perhaps a 3” Deringer in cal .50 loaded with 50 grains of pyrodex will give more ft/fps than a 8” pistol in cal. 45 loaded with 30 grains?

What surprise me is that a .490 ball loaded with 50 grains of 2F Goex Black Powder fired from a 10” barrel gave only 83 ft/lbs (112 joule), what’s the explanation behind that? A larger ball, more powder and increased barrel length should make it more powerful.

 

[Grenadier1758]

What surprise me is that a .490 ball loaded with 50 grains of 2F Goex Black Powder fired from a 10” barrel gave only 83 ft/lbs (112 joule), what’s the explanation behind that? A larger ball, more powder and increased barrel length should make it more powerful.

The pirate pistol with the stainless steel 10" barrel was loaded without a patch apparently. It had less velocity than the heavier conical with the same powder charge. I suspect there was a lot of blow-by even though the ball was a tight fit in the rifled barrel. Gas leaked by through the grooves.

 

[SmokepoleSam]

You have something wrong. Of course the 5.5in barrel gives a higher energy when you increase the powder charge. But you used the wrong information for the 8in barrel,you show only 35 gr of powder, a reduction from 46 gr. You must have looked at the wrong line. I can't find a 46 gr load in an 8in barrel, maybe I'm looking at the wrong chart. I'm not trying to be mean just pointing out what I see as an error.

 

[Powderandball]

You have something wrong. Of course the 5.5in barrel gives a higher energy when you increase the powder charge. But you used the wrong information for the 8in barrel,you show only 35 gr of powder, a reduction from 46 gr. You must have looked at the wrong line. I can't find a 46 gr load in an 8in barrel, maybe I'm looking at the wrong chart. I'm not trying to be mean just pointing out what I see as an error.

The comparison is intentional. If you increase the powder charge in a too short barrel, to a certain point it shouldn’t increase the velocity since the powder will burn outside the barrel. In this case the increased powder charge create higher velocity in the 5.5” barrel compared to the 8” barrel with less powder.

However, of course if you have an equal amount of powder the 8” barrel will have higher velocities than the 5.5” barrel. A .457 ball loaded with 45 grains of pyrodex fired from the 8” barrel gave 371 ft/lbs (503 joule), compared with the 5.5” barrel 46 grains only gave 350 ft/lbs / 474 joule.

For a deringer with a short barrel, I believe that the caliber has to be increased and the powder charge increased to get more ft/lbs out of it. I think that a .535 ball loaded with 50 grains in a 3” barrel might have the same energy as a .457 ball in a 8” barrel loaded with 30 grains. At this point it’s all speculation though. Is there any deringer or pocket revolver in cal .53 out there? I’ve only seen .45. Otherwise I’ll make one barrel myself. I don’t own a gun chronograph but I can make some ballistic gelatine and publish the results here.

 

[Sparkitoff]

Not exactly apples to apples but: I recently tried to get my 5" 1858 to shoot "as powerful" as my 8" 1858. Using the same balls and a chronograph to show FPS, I was able to tweak the powder charge and use over-powder wads, a certain amount of pressure, etc. to get the 5" the same as the 8" with less powder and just a ball seated over it (854 FPS average for each). This is only a 3" difference in barrel length and it took quite a few "changes" to get the same velocity. It is hard to believe with a 7" barrel difference the test in the original post showed the same "power". Maybe with a huge amount of tweaking - most of which caused more pressure - but not the lame way it was described.

 

[rodwha]

Mike Beliveau has a film out on the YouTube’s describing the power of cap and ball barrel lengths.

In .44s, the standard size 8” barrels give about 270 ft lbs of energy. The same load in the popular (if inauthentic historically) 5.5” barrel “Sheriff” models reduce that down to just over 200 ft lbs.

However the really short 3” and under “snub nose” or “avenging angel” type guns out there, of which Pietta makes repros of, have abysmally low ballistics. Something like 60 ft lbs, about on par with a .25 Auto.

So below 5.5” the cap and balls guns plummet in velocity and energy, and for my personally I prefer the added power of an 8” barrel.

On another forum a fellow using one of those cut down Pietta Avenging Angel pistols was able to get 847 FPS with a 200 grn Lee RN. That’s .44 Spl performance right there. Granted he used T7, but Swiss and Olde E have shown to achieve slightly higher velocities on average.

 

[Carbon 6]

To really compare, one should fire the Derringer, the Kentucky pistol and the Kentucky rifle, all with the same powder charge.
A velocity reading is what is needed.
Water is a funky medium for analysis because the harder you hit water the harder it resists.
So the difference in barrel lengths could result in a convergence of velocity vs resistance equaling the same penetration.

 

[Zonie]

To really compare, one should fire the Derringer, the Kentucky pistol and the Kentucky rifle, all with the same powder charge.
A velocity reading is what is needed.
Water is a funky medium for analysis because the harder you hit water the harder it resists.
So the difference in barrel lengths could result in a convergence of velocity vs resistance equaling the same penetration.

Your right when you say the harder you hit water the harder it resists.
This is the same sort of thing as wind resistance on a moving object.

The resistance to movement is a direct function of the velocity squared so doubling the velocity increases the wind resistance to four times as much. (2² = 4).

With water, the same thing is happening but because water is so much denser than air, the change or effect becomes much more noticeable.

 

[Carbon 6]

Your right when you say the harder you hit water the harder it resists.
This is the same sort of thing as wind resistance on a moving object.

The resistance to movement is a direct function of the velocity squared so doubling the velocity increases the wind resistance to four times as much. (2² = 4).

With water, the same thing is happening but because water is so much denser than air, the change or effect becomes much more noticeable.

Yes, the point I was trying to make is that, it is possible that the increased velocity of the Kentucky pistol created greater impact resistance resulting in equal penetration.

This however does not mean that they are equal in power, as the bullet with higher velocity will impart greater foot pounds of force regardless of penetration.

At least it would explain the test results.