Velocity wise, which calibers are least affected by barrel length?

F

fallingrock71

New member
Please pardon my laziness. Just as the title states I'd like to know which calibers lose or gain the most by barrel length. Just curious mostly, but I did see a Ruger SRH Alaskan in .454/.45lc at a gun shop yesterday. I've been trying to talk myself into/out of buying that one for a while now. It set the wheels a turnin' again

thankyakindly
 
the surge in production and use of short barreled semi automatics has created in a huge surge in design and development of bullets that work in short barrels.
 
I hope you mean new ammunition. Most of the bullets have remained unchanged, and don't care what length barrel you propel them through. ;)



As for cartridges that lose the least velocity in short barrels....
My experience has shown .25 Auto, .32 S&W, .32 Auto, and .38 S&W to be the best there. But, they lose very little, because they don't have any real velocity to begin with. ;)
 
ballistics by the inch (see link above in post 2) will tell ya out of both test barrels and actual guns.

Study and compare with other rounds. Keep both energy and momentum in mind.

tipoc
 
There are too many variables for a meaningful answer, and in handguns such factors as the revolver barrel-cylinder gap need to be taken into account. The best approach is to decide what gun you prefer, and then choose a barrel length and load that will give you the results you want.

(Just for one variable: It is common for the bullets of factory cartridges of the same caliber, out of the same box, fired out of the same gun, to vary as much as 50-75 fps in velocity.)

Jim
 
Providing all things are equal (same burning rate of powder and or pressure) the cartridge with more cubic inches of bore to burn the powder effectively should in theory loose less velocity per inch of barrel. Typically though the smaller the bore capacity the slower the powder needs to be to equal the same performance. In the case of these handguns cartridges things are not always equal though. It largely becomes a ratio of case capacity vs bore capacity.

Larry
 
Based on what I've observed any differences between various chamberings are pretty small. All chamberings, rifle and handgun, shoot faster from longer barrels. Most of my detailed observations are with rifles, but I see similar patterns with handguns.

I've noted that most chamberings seem to have a "sweet spot" on length where going shorter results in fairly large drops in velocity, but going longer doesn't seem to help much. Gains will be very small and huge increases in length are needed for any measurable gains in speed.

There is a reason for the common lengths we see guns chambered in. 30-30's are usually around 20", most standard rifle chamberings are about 22", most magnum's are 24", with a few specialty guns with barrels longer. With handguns typical autoloaders are around 4-5" and magnum revolvers are 6-8". The new super magnum handgun rounds are usually around 8-10". If you stay pretty close to those lengths with those chamberings you don't lose or gain much by going a little shorter or longer.

But when you alter length significantly, especially shorter lengths, velocity drops significantly. A 30-06 doesn't lose nearly as much cutting a 24" barrel down to 20" as most people think. It still has over 83% of the length it started with. But a magnum revlover round tested with an 8" barrel that is used in a 4" barrel only has 50% of its original length. Velocity loss will be much greater percentage wise. That would be comparable to shooting our 30-06 in a 12" barrel vs the 24" it was tested in.
 
This subject is wide open for a lot of discussion. So time for my two-cents-worth experience:

When I first started shooting, I was a long barrel fanatic. My first three guns had a 6", 8 3/8", and 8 3/8" barrels respectively. I thought short barrels "wasted" energy, to describe as briefly as possible.

I recently got a chronograph and proceeded to test a whole bunch of 38 and 357 rounds of all weights and power combinations.

My 357's are 3", 4", 6", & 8 3/8". So I got to shoot all this ammo through 4 different barrel lengths - one right after the other. I had so many different rounds, this took 2 days out at the range. It was an arduous process (well, as "arduous" as shooting a gun gets ;-)

To generalize my findings: Basically, after 4", most rounds do not see a significant velocity increase; in fact, many decreased through the longer barrels (target loads mostly). Only the hottest loads, with the slowest powders, with the heaviest bullets showed significant velocity gains.

I wouldn't have guessed that. Good learning experience. "Ballistics by the Inch" is a good informational site. I've been there. But I don't think it necessarily tells the full story. On thing that my findings taught me - and admittedly, there's some speculation here - is that the cylinder/barrel gap in revolvers plays quite a role. I think if there were no gap there for gasses to escape, my finding would have been a lot different. I don't think Ballistics by the Inch data accounts for that gap.

Also, I would suspect that things are a little bit different with the big-bore guns. If I had to guess, there probably is a barrel length were returns diminish, but it's probably something a bit longer than 4" - maybe 8 or more. But at some point, that pesky cylinder/barrel gap will come into play.
 
From Fallling Rock

Please pardon my laziness. Just as the title states I'd like to know which calibers lose or gain the most by barrel length. Just curious mostly, but I did see a Ruger SRH Alaskan in .454/.45lc at a gun shop yesterday. I've been trying to talk myself into/out of buying that one for a while now. It set the wheels a turnin' again
Click to expand...

Well what calibers are you considering and barrel lengths are you thinking of?

tipoc
 
Nick_C_S:
Also, I would suspect that things are a little bit different with the big-bore guns. If I had to guess, there probably is a barrel length were returns diminish, but it's probably something a bit longer than 4" - maybe 8 or more. But at some point, that pesky cylinder/barrel gap will come into play.
Click to expand...

Have you seen this? Cylinder Gap Tests

Jim
 
Velocity...

Is determined by
a. The ratio of propellant weight to bullet weight (more powder, less bullet goes faster [everything else equal]), and
b. The expansion ratio of the firearm (longer barrel gives more velocity).

So, in general, a larger bore (greater expansion ratio) looses less velocity than a smaller bore firearm AND a larger chamber - larger powder charge - looses less velocity than a smaller chamber firearm [everything else equal].

Yes, there are many other factors. My comments are a brief overview of the question.
 
It may be interesting in your situation to consider whether you would rather have a lighter framed .44mag in 4" (Redhawk or 629) or the heavier framed Alaskan in .454.

According to QuickLoad calculations using just W296 and 300 gr bullets for both you should get 1,077fps/772 ft-lbs, with the 4" .44 mag. For the 2" .454 you can get the same weight 300 gr bullet at 1,005fps/673 ft-lbs. at first blush it looks like the 4" .44 mag slightly wins.

However, I believe the 2" .454 might be able to be pushed to better performance than the 4" .44 mag by using even heavier bullets and slower powders. Getup to 350 gr or more and I bet the .454 wins easily.
 
I was looking at the .357 magnum data and it seems that the heavier bullets suffer less velocity loss when going to a shorter barrel.
Click to expand...

Sometimes that is true. It's also true that they usually begin with less velocity and retain what they do have longer. The heavier rounds, like 158 gr. also have greater momentum.

Until the op returns it's hard for me to know exactly what he was looking for.

This article by Stephen Camp may be of some help.

http://hipowersandhandguns.com/can_less_be_more.htm

tipoc
 
How can it be "hard" to know what he's looking for? He wants the .454 Alaskan, with a 2" barrel. We've seen ballistic data a coupla' posts ago. A 300 gr. bullet going 1,007 fps. I wouldn't do it. Consider that the same load from the barrel length it was designed for is going more like 1,500~1,600 fps.
Some time ago, I read an account where a guy was surprised by an old giant grizz in Alaska. He used that same gun. He had no time for nuthin' and couldn't recall if he shot once or twice. The bear literally fell down dead, just inches from the shooter. It just wasn't that guys' day to die.
In another story, 2 guys had a guide fly them into a place where they hoped to find their monster. They saw him just after the plane stopped rolling, and ran off to shoot him up. They were both packing .500 S&W's, with 10" barrels. Both guys emptied their guns into that bear, hitting center of mass, and the bear did not stop. The guide finished it with his .45/70 lever gun. Oddly enough, that rifle is less powerful than those pistols, but the guide knew where to aim.
In yet another story, a hiker was being followed by a big brown bear in AK. He had only his AK47 with him. It took 17 rounds to stop that one.
In another story, a long time AK resident and trapper had a big bear come into his cabin. He hit it 5 times with his .270. He and the bear were both found dead.
I talk to oil people once in awhile who work in Alaska. For them, it's a 1 oz. slug in a 12 ga. 3" magnum. That's roughly a 500 gr. projectile going roughly 1,500 fps. I would follow their advice.
 
So, in general, a larger bore (greater expansion ratio) looses less velocity than a smaller bore firearm AND a larger chamber - larger powder charge - looses less velocity than a smaller chamber firearm [everything else equal].
Click to expand...

Exactly.
 
A 9mm with a full charge load is less affected by a real short barrel then any caliber I've tried, if that helps any.
A guy needs his own chronograph for such experiments.
 
Looking at it another way, magnum revolver cartridges have the most to gain from longer barrels. High pressures coupled with high powder capacity. Autopistol cartridges, not so much.
 
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