Barrel Length: Does It Matter For Velocity
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- เผยแพร่เมื่อ 10 ม.ค. 2025
- Welcome to the Ron Spomer Outdoors Podcast! In this video, I answer a listener's question about barrel length and if it really affects velocity.
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Who is Ron Spomer
For 44 years I’ve had the good fortune to photograph and write about my passion - the outdoor life. Wild creatures and wild places have always stirred me - from the first flushing pheasant that frightened me out of my socks in grandpa’s cornfield to the last whitetail that dismissed me with a wag of its tail. In my attempts to connect with this natural wonder, to become an integral part of our ecosystem and capture a bit of its mystery, I’ve photographed, hiked, hunted, birded, and fished across much of this planet. I've seen the beauty that everyone should see, survived adventures that everyone should experience. I may not have climbed the highest mountains, canoed the wildest rivers, caught the largest fish or shot the biggest bucks, but I’ve tried. Perhaps you have, too. And that’s the essential thing. Being out there, an active participant in our outdoor world.
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More specifically it’s bore volume that’s important, not barrel length. For example a 27” .264 barrel has the same amount of volume as a 20” .308.
Barrel volyme/vs case volyme. Go with 6x case volyme.270 win whants 29,3 inch and 308 19,8. 222 rem 18 and 22 250 whants 29.
Always a better day when Ron post.
This actually an outtake from a previous video.
I have a love/hate relationship with Ron Spomer videos. I watch everyone and then gripe to my wife and she says," why do you watch it then?" Keep up the good work, Ron.
A pretty simple question. The barrel has to be long enough for the powder pushing a given bullet to completely burn and use all it's energy before the bullet exits the muzzle. Short barrels need fast powders, long barrels can make use of slow and large powder charges and cutting them back leads to a lot of muzzle flash and velocity loss.
It does make a difference yes, but it depends on your requirements and purpose for the rifle. I’m currently busy with load development on my CZ557 7X64 Brenneke. It has a 20.5” barrel. So I have to be careful of the type of powder I use to ensure I have burnout. But it’s an awesome light rifle and hunts great!
I just bought a 6.5-300 weatherby vanguard with a 26 inch barrel, I love it. Thanks Ron!
Love to compare that with my 26 Nosler with its 26" barrel.
@@dundonrl That would be really cool!
Thanks for the content. I'm surprised the 22 lr starts to slow down after the 16.5" of a barrel. Glad that's the longest I run in my 22 lr's currently.
If you get into the Eley or Lapua data you'll see that the test bbl is a 24" one I believe. Due to the drag inside the bbl it is said to make the ammo velocities more consistent.
MDT did a video on this a while back with 308 winchester, they matched the rifling and put two barrels together.
Thank you
I’ve seen people use 16 or 18” on 300 win mag. I look at them in disgust
Depends upon cartritage and its pressure/powder capacity.
Ballistics by the inch has charts of carious calibers and bullets.
It depends. Barrel length equates to dwell time and pressure build. You obviously can only allow a set maximum pressure before bursting the chamber and bullets can only go so fast etc. But using a longer Barrel and the right powders you can get more velocity but it will eventually top out at a set length per cartridge and caliber.
I have a 44 magnum lever gun with 24" octagon barrel and I don't know if the length adds any velocity but I do know that it adds weight.
MDT did a video on this, with a 70 inch barrel that they cut back. if I remember right velocity only dropped off under 40 inches. the drop off was consistent until 24 inches after which velocity dropped steeply. They only tested 308 175gn's. I wish they tested different bullet weights and powders but still it was interesting.
Velocity dropped with their first cut, but it was minimal. It was somewhere around the 32-36 inch mark that the difference started to be more pronounced.
Thanks
Yup. Plenty of assumptions. I might have mentioned this before but my 10” Contender .22LR match chamber produces the fastest velocity with most super sonic ammo I’ve chronographed, including CCI minimag. CCI Standard Velocity is virtually the same as my 18” bolt actions. The slowest? My 26” barrelled 1930s Mauser single shot bolt action. It has a very tight bore and the chamber is not as tight as the TC but seals very well. I only shoot it open sighted but it is amazingly accurate with even poor quality ammo. The bore is so tight a patches .22 jag has to be really pushed hard unless I trim the corners. Which could explain why it is slightly slower. Thanks for the video and take care!
To study this problem , we need to get into interior ballistics , which might be a little too technical . If you get more speed out of a cartridge because of a longer barrel , you are getting more efficiency right ? Well , that is related (among other things) to the expansion ratio. The two extremes might be a 22LR and a large capacity small bore rifle catridge ( The 22 Eargesplitten Loudenboomer comes to my mind... just kidding !! )
Nest thing ya know bullet manufacturers will start listing the COF (coefficient of friction) of their bullets.
Can you please do a video on terminal ballistics - specifically neck length? i.e. the distance the bullet travels before expansion or cavitation. Some say that the ideal distance is 0; I would think you would want several inches of penetration before expansion.
While a 40" barrel isn't practical, I find it ironic that people go on and on about this cartridge vs that cartridge (308 vs '06, for example), when the difference between them isn't any more consequential.
With that said, given the above cartridges, you could have a longer barreled 308 perform the same or better than a '06, with considerably less recoil, due to the cartridge and gun weight.
I can't help but wonder what's the best large game cartridge for an 16" carbine.
When you're shooting distance, especially at higher elevations, 30 or 50 extra feet per second of velocity at the muzzle matters. And with high BC bullets that will carry that extra velocity even further, you don't want to sacrifice velocity for convenience. If you are content to shoot targets at a hundred or two hundred yards then the above is not for you.
It's fun (for me, anyway) to think about this from a physics point of view, too; it's not, of course, barrel length per se. It's the amount of time that the pressure has to work on the bullet - i.e. barrel residency time of the bullet, which is determined by bullet weight, and by the powder's quantity and burn rate, which in turn determine the pressure curve. Put another way, that residency time for a given powder volume and burn rate (force) depends on bullet weight (mass), in the classic F=MA equation.
In the case of the low velocity, small powder charge .22 LR, the bullet's barrel residency time is sufficiently long that nearly all of the powder is burned in a shorter barrel, such that any remainder of unburned powder wouldn't contribute to higher pressure to continue accelerating the bullet if a longer barrel - with increasing internal barrel volume behind the bullet as it moves toward the muzzle - were used (Boyle's Law). In other words, the bullet is essentially at equilibrium - bullet drag on the rifling balanced against the pressure behind it - over a short travel path to the muzzle. Any longer barrel, and the pressure would drop, slowing the bullet's travel from friction, so a longer barrel is counterproductive.
With larger centerfire cartridges, high speed photos of muzzle blast make clear that in many cases, a large amount of powder is unburned or incompletely burned*, and a longer barrel would allow additional barrel residency time for that powder to burn, which MIGHT increase the pressure (force) behind the bullet and keep accelerating it. In other cases, the powder has been substantially all burned, but the residual pressure is still enough to continue accelerating the bullet anyway - until the equilibrium point is reached, at which time the bullet would only decelerate from friction if the barrel were any longer. That length appears to be as much as 40 inches for a seriously "overbore" cartridge.
Since a lighter bullet will accelerate faster than does a heavy bullet for a given pressure - again, F=MA - the same powder charge and resulting pressure curve could lead to the bullet reaching the muzzle before all the powder has burned, "throwing away" the potential additional force the fully-burned powder could have delivered - whereas with a heavier, more slowly-accelerating bullet, the powder may have completed burning, resulting in ~similar muzzle velocities despite the difference in bullet weight. In either case, a longer barrel is advantageous, but potentially far more so for the lighter bullet. The proper response, of course, is a different, faster-burning powder for the lighter bullet, as has long been known.
* Incomplete burning - a large amount of it - is on display in spades with an old S&W Model 53 revolver I have. The .22 Jet cartridge is really a rifle cartridge, and when fired in the revolver, the muzzle blast and flash is Chernobyl-quality. I tell people it's the ultimate defense weapon - if you miss, the muzzle blast will incinerate the target anyway. It would give Vesuvius a run for its money - and it attracts LOTS of unwanted attention at the range.
As always, thanks for the video - it's always interesting to watch and listen, and get the mental gears turning.
Agreed. Thanks for writing out your idea
The thing is hot .22 KR is still gained past 24”. And more importantly 60 grains of black powder in .58 caliber worked well. If that tie then I would guess a .30-06 with 60+ grains of smokeless powder with 2-8 times the energy will by fine probably to something like 60” depending on how slow the order is. I would love someone to tack this “for academic purposes”!!!
I would love it if I could get in contact with some folks who'd be interested in looking into the creation of a modern falling block receiver. Specifically, designed for today's magnum cartridges so that an inch of receiver could support as long a barrel as is practical. You'd potentially have a stiffer and more accurate receiver. An incredibly long barrel allowing for the benefits mentioned, all in a rifle the same length as your buddy's but running much faster.
What about a Ruger Number 1? A 28" barrel results in an overall length of 42.5" overall length. A 24" barreled M77 overall length would be 44.75" overall length - 2.25 inches longer, with a 4" shorter barrel.
I have been wondering this for a muzzleloader, would my gains in a 30inch barrel over a 24 justify the 400 increase in price tag?
I watched a video on the tube. I can't remember who did the test but they started with a crazy long barrel. Then after the shoots they cut it down. I want to saw an inch at a time but dont hold me to that.
My 303/25 had a 19.5 inch barrel, the powder was still burning outside the barrel, I believe it lost lots of its performance
This is actually incorrect. With 30.06, it's about 100 fps difference per inch. Remington ammunition labs agrees with this. I'll take my .308 with 24" barrel over 300 win mag 18" barrel all day long.
Didn't somebody show that I believe they started with an 8 foot and after each round fired they would cut off an inch if memory serves me at 38 inches or less they start to loose speed.
A 16 inch barreled .375 WSM Long Action can be transsonic out to 1600 yards.
3.6 COAL.
I am the future.
Well Ron, been shooting and reloading cartridges for 50+ years…….the critical element is the powder! Match the powder and the powder charge to the barrel length. Naturally all safety and laws of physics apply!
Also worth noting that black powder gains much more from barrel length than smokeless
That sure seems counterintuitive, because black powder is an explosive, which smokeless is not, and burns MUCH faster than smokeless in free air. In a chamber, the pressure rise and fall is also much faster than for smokeless. Smokeless, of course, produces a much higher volume, of hotter gas, in its deflagration, producing much greater total chamber and barrel force against the bullet - but you'd think that would indicate that long barrels were made for smokeless. Yet everywhere you look, black powder shooters talk about 30 inch-plus barrel lengths. Curious.
@@MrGsteele while it does burn faster it produces less gas expansion during the burn so you need extra case volume and barrel length to get a bullet up to speed and stabilized
@@justahologram2230 Ah - I think I see what you mean. In the case of black powder, the total volume of black powder used is huge compared to smokeless?
@@MrGsteele correct, in the case of the .45-120 it needed the full 120 grain load of BP and at least a 34" barrel to go anywhere close to 1600fps with a 500gr bullet
In general I'd agree with the 40" max length. I read where someone did the test... with the 308 I believe.
40" was about the max I believe, in that person's test.
I used to always hear that the .22 lr in a rifle, had the best performance in an 18" barrel.
I got 1000 fps from a 5 1/2" revolver barrel, and 1200 fps from a Marlin 22" barrel using CCI Mini Mag hollow points.
But someday I'll retest with one of my older Remington M521 rifles. (25" barrels)
Too bad we can't seem to ever get the 1400 plus fps out of those higher velocity .22 lr ammo rounds like they claim.
I'll need to test them someday with the 16" through 22" barrels.
Still, the ammo and the chamber and throat dimensions of the barrels, and then the bore conditions.... the weather and altitudes, etc..... too much to chew on, or care about!!
I still prefer all rifle barrel lengths of 24" to hunt with, if not a tad longer. (if possible)
They'll all still kill game, and break ear drums!
MTD did it starting with a 6 foot long barrel.
Mdt did this with a 308 I believe on there you tube channel
I believe that if we had a barrel 1000 yards long that we could set new accuracy records if measured from the breach face.
By placing the muzzle on the same spot on the target we could accomplish 0 size 1000 yard groups measured from the breach face. Lol. Transportation could be a problem!
The NAZI Super Guns had powder containers on the barrel that the powder gas from firing would ignite and boost the velocity of the round. That concept could be used at the king of two miles . How well it would work, is anyone's guess.
True
My 9mm EDC is a Glock 19 with a 22 inch barrel. Joke
What person, Patron or not, does not know longer barrels mean more velocity, are you running out of real things to talk about or broadcasting to a kindergarten class
Feel better now?
Yay i pooped today!
There is a lot of new hunters out there that don’t know much about guns and so forth so sometimes it’s good to do a refresher on such things! It’s been over 60+ years since I started hunting, collecting and reloading and a refresher never hurts even for us old guys because some times we even for get, just ask my wife 🤔😳😂 thankfully for me my wife says length doesn’t matter 🤔😳😂
You win the most immature post of the day! Irony…
26 inches is borderline practical max in the field. Slow powders primers chambers bullets ... 100 fps? Bah!