Barrel length and velocity of patched balls

[M. De Land]

I have never had a muzzle loader with over a 36 inch barrel and have done very little chronographing of round ball, muzzle loading velocity, so manual reading of barrel length and velocities is the only reference I have had to draw from.
I have done quite a bit of chronographing of black powder and duplex black powder loads from brass cases and lead bullets but this is probably comparing oranges and banana's , no?
It looks to me from my limited first hand knowledge that much barrel length beyond 30 inches adds very little if any thing in black powder velocities as the expansion ration seems to be efficiency maximized in that length but would like to hear from others who have actually tested and recorded velocities along with extreme spread (ES) and standard deviation (SD) of patched ball loading in various barrel lengths and calibers.

 

[54ball]

I have never had a muzzle loader with over a 36 inch barrel and have done very little chronographing of round ball, muzzle loading velocity, so manual reading of barrel length and velocities is the only reference I have had to draw from.
I have done quite a bit of chronographing of black powder and duplex black powder loads from brass cases and lead bullets but this is probably comparing oranges and banana's , no?
It looks to me from my limited first hand knowledge that much barrel length beyond 30 inches adds very little if any thing in black powder velocities as the expansion ration seems to be efficiency maximized in that length but would like to hear from others who have actually tested and recorded velocities along with extreme spread (ES) and standard deviation (SD) of patched ball loading in various barrel lengths and calibers.

In short.....
Longer barrels = more velocity.
It’s been proven again and again.

 

[William Lincoln]

Long Rifles were long for a reason. Accuracy and velocity.
Sight radius. The ability to use a wide variety of powders and
extract all the energy.

 

[The Crisco Kid]

Like most things it's compromise. A longer barrel gives a higher velocity and a longer sighting radius while a shorter barrel is more portable. I'll take the short barrel and a little less velocity for hunting and I haven't noticed I shoot any better with the longer barrel offhand at a match. Or maybe I should say I don't shoot any worse with the short barrel.

 

[SDSmlf]

Based on chronograph data from long ago (no I don’t have the numbers available as they weren’t all that important at the time) there was less velocity gain with finer powder (think 4F and 3F) when used in longer barrels than with courser powder (2F and 1F) in the same barrels. There are guidelines, but any actual rules will depend on your barrel, its length, projectile (and patch), powder granulation and powder manufacture. Think Goex vs Swiss vs Elephant vs any other powder manufacturer) Just one of those things that you have to confirm if important to you.

 

[John Stark]

Deleted due to missing a sentence......

 

[M. De Land]

In short.....
Longer barrels = more velocity.
It’s been proven again and again.

Well, I'm not so sure that is actually accurate information because when the powder (fuel) is burned up say in 28-30 inches , have a gas leak at the rear (flash hole) and still have 14 inches of barrel to traverse, what would make the ball go faster?

 

[Appowner]

I dabble in long range shooting with the other guns. And there is a distinct point in length where a longer barrel no longer pays dividends worth the effort. A big in depth study in Texas concluded that for modern weapons a 21.75 inch barrel was optimum for any caliber. Not claiming it's true but simply throwing out what I've read.

In the 70's when I got my first ML, a TC Renegade, the destructions said to never use a powder charge greater than 120 grains. Being the curious fellow I am I did some shooting with 120 grains and found I was throwing raw powder out the end of the barrel.

Barrel length impacts a great many things. As does powder charge, ball fit, the weather that day and so on. So imagine if you will a rifle with a 10 foot barrel. Put it on a bench to eliminate as much of the human factor as possible. Now consider what the performance might be out of that thing? Ah............ there is a limit to barrel length! And to my thinking that's whatever it takes to burn the entire powder charge.

 

[olskool]

generally, Longer barrels give the propellant force/pressure more time to work on propelling the bullet. i have heard all kinds of things in my life. one i have heard the most is a longer barrel has more time to burn the powder, this is no true. the explosion takes place, and the powder is burnt then and there., then the gas does its thing as it builds pressure, this is true with smokeless 100%, but black powder you will see embers come out the end of the barrel and small grains will still be burning, but that will affect velocity very little if any. i had one fellow tell me that when the bullet left the muzzle for about 30 yds it actually got faster! i told him no, it is like throwing a baseball, when it leaves your hand/muzzle, that was as fast as it would ever be, at that point it would only loose velocity. then i have heard this a couple of times, in fact the other day a friend of mine told me this. he said he had a magnum rifle of some sort, and it was so fast if you shot a deer with it at close range the projectile would go through so quick it had no time to expand! i told him it was like throwing an egg at a wall. i asked him, if you barley lob it at the wall or throw it with all your might what would do the most damage to the egg? he got it then. old tales die hard,,,,,,,,,,,,,,,

 

[ETipp]

IMO, for practical ML hunting distances it matters not on barrel length, as long as accuracy is there. One thing is most surely true. The maximum velocity should be where projectile leaves the barrel at the time the gasses are completely burned up. If the gasses are burned up only half way down the barrel, then from then on the projectile will be under more drag and reduce the velocity of the projectile due to that added drag.

Again, I do not think it will make much difference either way on game at normal ML hunting distances.

 

[Kmcmichael]

The round ball loses velocity so badly, it largely negates the higher velocity achievable with increases powder.
I just test until I get the most accurate load and use that at whatever distance is common for the proposed target. One might increase or decrease the charge for a different distance.
My .54 40” bbl shot best with 95 one day and 100 the next @ 1900 FPS. ( generally under 3” at 82 yards)
My .40 44”bbl shoots 27.5 grns very well but shoots very low at longer distances. Double to 55 grns and it is on at 82 yards with decent groups. At 70 grns of 3F it will reach 2400 FPS. I saw no advantage to that load.
Each barrel is a law unto itself, but I do believe with black powder barrels beyond 36” will likely give increased velocity, but is it worth it ballisticly.

They do however look way cooler.

 

[Compressorguy]

I haven’t performed actual testing but the ballistic simulator below supports the idea that barrel length beyond a certain point doesn’t add much velocity. Taking my Pedersoli .50 with 39” barrel for example with a 70gr FFF charge, 178gr .490 RB has a MV of 1,839 fps and ME of 1,337 ft/lbs with 99% of the powder burnt. Increasing the barrel length to 44”, with all else the same yields 1,869 fps and 1,381 ft/lbs. “Only” a 30 fps and 52 ft/lb increase respectively and shows all the powder burnt at 39.2”. Is it ironic Pedersoli chose 39” for their barrel length? Hard to say but adding 5” more barrel would add quite a bit more forward weight, especially in an unswamped barrel for “marginal” gains. Interesting stuff!

Link:

https://www.p-max.uk/cgi-bin/black_powder.cgi

 

[Kmcmichael]

That raises the question; would 2F, being slower burning achieve more gains from the longer barrel?

 

[Compressorguy]

According to the simulator, Nope. At least not at 44”, or even out to 48” or beyond practical. Interesting to play around with the simulator, plug in your data in the link above.

 

[TCMonts]

I may need to go get some popcorn for this one.

 

[Compressorguy]

I may need to go get some popcorn for this one.

Yeh, I don’t much care about diving deep down this rabbit hole. Just found this link and the comparisons interesting and enlightening at best. Otherwise I just work up loads to hit what I’m aiming at, if that happens, I’m happy.


It is interesting to know how the loads are performing though, especially when asked from bystanders comparing MV/ME to their modern cartridge guns.

 

[Mulebrain]

Well what do we have here? Would be good if folks just did a search

Barrel length and velocity?​

https://www.muzzleloadingforum.com/threads/barrel-length-and-velocity.112930/

 

[tenngun]

Lyman did a lot of testing with barrels from 28” to 43”. Charge for charge as patching ball and lube was the same the got about 10fps per inch. Longer barrels got more advantage over shorter barrels when one was at the top end of powder charges, but few guns shoot their best at biggest charges
And we could see even a loss of velocity when we hit bigger charges, or gains of less then ten fps
As pointed out above the ballistic of ball is so poor that high MV doesn’t do much down range, and even trajectory differences of ‘shooting flat’ become unimportant after about fifty yards.
A .54 at 1100 fps slows to about 850 at a hundred yards.
Big chargers and long barrels can get a .54 up to 2200fps, but that slows to about 1100 at a hundred yards
Regardless of barrel length most shooter get their best groups in the 1500 fps range.
Old guns from the UK and far west Europe tended to have longer barrels, American guns followed suit. Central European guns tended to be shorter. Down range they preformed the same.
I like long just because it looks right to me. I don’t find it unhandy in the woods. However there is no practical reason to have long.
An exception is shooting shot. But there are lots of tricks to get long performance from short guns

 

[Uncle Miltie]

The most accurate muzzleloaders ever made had barrels under 30".

 

[54ball]

Well, I'm not so sure that is actually accurate information because when the powder (fuel) is burned up say in 28-30 inches , have a gas leak at the rear (flash hole) and still have 14 inches of barrel to traverse, what would make the ball go faster?

For the most part it is accurate information.
Now there’s always the “hypothetical” 10 foot long barrel with a squib load stuff.

For the most part......
In the real world.......
Using realistic barrel lengths.....
Using realistic charges.........

A longer barrel will give more velocity.

This is true from a handgun all the way up to a naval rifle.

Now this higher velocity may not be of any real world use.