Muzzle Velocity Comparison for Unequal Barrel Lengths

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A formula for all? I don't think so....

Go to Buffalo Bore's site and look at their results. They list the velocities for each load with different barrel lengths.

At first, their 125 gr .357 stuff goes slightly faster with a barrel length increase but then peaks and actually slows down as the barrel gets longer and longer while their 158 gr loads just go faster as the barrels get longer.

It's not only the gun's barrel length that determines velocity but also the characteristics of the powder used. Buffalo Bore's 125 gr stuff must burn really quickly or something because it seems to have run out out of steam before exiting the longest barrels.

In order to make up a formula, one would have to quantify the expansion & burn rate of each bullet with each individual powder or powder combination. I guess one could come up with a formula for a load, a unique one for that load only, but it'd be difficult. The formula would be good for that specific loading only.
 
A formula for all? I don't think so....

Go to Buffalo Bore's site and look at their results. They list the velocities for each load with different barrel lengths.

At first, their 125 gr .357 stuff goes slightly faster with a barrel length increase but then peaks and actually slows down as the barrel gets longer and longer while their 158 gr loads just go faster as the barrels get longer.

It's not only the gun's barrel length that determines velocity but also the characteristics of the powder used. Buffalo Bore's 125 gr stuff must burn really quickly or something because it seems to have run out out of steam before exiting the longest barrels.

In order to make up a formula, one would have to quantify the expansion & burn rate of each individual powder or powder combination with each bullet. I guess one could come up with a formula for a load, a unique one for that load only, but it'd be difficult. The formula would be good for that specific loading only.
 
One thing I found Very interesting (though not unexpected) was that while there was a significant difference per inch with the .357 when looking at lengths from 2" to say 8" there was much less difference with the .45 ACP. Basically slow vs fast powder.
Click to expand...
There's also the bore volume factor.

For the velocity to increase as barrel length increases, there has to be gas pressure pushing on the bullet with force that is greater than or equal to the retarding force of bore friction. The larger the bore diameter, the faster the bore volume grows as the bullet moves down the barrel. That means that you have to have a lot of gas volume to fill it up and maintain pressure on the bullet. That's easier to do with smaller bores and that's why it's not uncommon to see that cartridges with large bore diameters tend to suffer less severely from reducing the barrel length.
 
M.E. vs length barrel

https://www.genitron.com/Basics/Common-Handgun-Cartridges

Perhaps a tangent but this thread found pursuing a chart that depicts "all thing equal" in Muzzle Energy for calibers, adjusted for Barrel Length.

Anyone & everyone takes the EASY road of taking notes at range for Typical to Caliber barrel length M.E.s ... little thanks for that when SO MANY lengths of barrel can be had for a caliber.

We should be able to select a legal barrel length and then run tests for each of the calibers to post. e.g. one might find it interesting that with same barrel length, 357mag bests the infamous 223/556 in M.E. !!!! (I interpolate, I think)
 
Sunfish said:
We should be able to select a legal barrel length and then run tests for each of the calibers to post. e.g. one might find it interesting that with same barrel length, 357mag bests the infamous 223/556 in M.E. !!!! (I interpolate, I think)
Click to expand...
Interpolate? I'd call it extrapolating. You've gone from comparing muzzle velocity in one chambering as it varies by barrel length to comparing muzzle energy for two very dissimilar cartridges.

I think this thread deserves to be left alone. Closed.
 
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