Muzzle velocity Hawken vs Longrifle

[oblaze]

Oblase.......I'm in Central Pa. , with a camp north of Snowshoe.

That's only 3 hours away. Easy weekend trip distance.

 

[LME]

.
Didn't play out in my chronograph testing.


That's what I found. Two 54 caliber rifles both 1:48 twist. One barrel 32", one barrel 28". Both loaded with the same identical load components. Same day, same everything. Conventional wisdom says the longer barrel is faster. NOT SO! The 28" barrel was faster. The only difference in the two was the 28" barrel was significantly tighter.

I was told years ago by a excellent shooter that the ultimate load for a rifle was one where the powder burned out about two inches before leaving the muzzle? It was said the accuracy was in the last two or so inches of the barrel and you wanted the bullet to coast those two inches with nothing pushing the bullet? If this is right or wrong I personally don't know. I have never heard it before nor since. Has any of you fellows heard anything like this?

 

[French Colonial]

I was told years ago by a excellent shooter that the ultimate load for a rifle was one where the powder burned out about two inches before leaving the muzzle? It was said the accuracy was in the last two or so inches of the barrel and you wanted the bullet to coast those two inches with nothing pushing the bullet? If this is right or wrong I personally don't know. I have never heard it before nor since. Has any of you fellows heard anything like this?

HMMMM.....

I am not an expert on internal ballistics but just from observation I would question this, any rifle I have seen shot has had some amount of gas exiting the muzzle.

It may not be pushing the projectile very much, say in a long barrel .22, but the fact that some gas is escaping from behind the bullet would lead me to believe it is still having some push, even if not very much.

Maybe there is a ballistician on the forum that can answer definitively.

 

[Grenadier1758]

Even if the powder has all been burned, that previous burning has built up considerable pressure to push the bullet out. @LME has heard an interesting theory, but that theory won't stand up to observation. The volume of gas in the barrel is under compression due to the burning of the powder charge. That ball is definitely not coasting after the powder is burned.

 

[LME]

HMMMM.....

I am not an expert on internal ballistics but just from observation I would question this, any rifle I have seen shot has had some amount of gas exiting the muzzle.

It may not be pushing the projectile very much, say in a long barrel .22, but the fact that some gas is escaping from behind the bullet would lead me to believe it is still having some push, even if not very much.

Maybe there is a ballistician on the forum that can answer definitively.

I don't know either but I have read a lot on ballistics, studied the geometry of a barrel and everything in between and have never seen this in print. I can understand that certain things can change what load works best in a certain rifle I think speed and rifling have to be in harmoney to be accurate and that being the main thing. I also know that it is better to be a shade weak than too strong a charge if you are chasing accuracy. My favorate M.L. rifle shots 90 grains accurate but I backed up to 80 grains to put my velocity at .22 rifle speed and my accuracy remained the same. If I went to 100 grains the pattern opened up letting me know she is to hot. This got me to thinking it may be where this story got started. I figured some one in our group might have heard this before and could shed some light on the subject?

 

[LME]

Even if the powder has all been burned, that previous burning has built up considerable pressure to push the bullet out. @LME has heard an interesting theory, but that theory won't stand up to observation. The volume of gas in the barrel is under compression due to the burning of the powder charge. That ball is definitely not coasting after the powder is burned.

I was thinking the same thing . It is why I posed the question. I did consider that if the powder has all burned up there might be something occuring that might change how the ball performs but for the life of me I can't come up with any logical reason?

 

[Old Hawkeye]

I was told years ago by a excellent shooter that the ultimate load for a rifle was one where the powder burned out about two inches before leaving the muzzle? It was said the accuracy was in the last two or so inches of the barrel and you wanted the bullet to coast those two inches with nothing pushing the bullet? If this is right or wrong I personally don't know. I have never heard it before nor since. Has any of you fellows heard anything like this?

How do you figure out or measure where the "powder burned out"? What is so special about the "last two inches" of the barrel regarding accuracy? I think your "excellent shooter" is full of it! This is ,however, the first I've heard this "theory" & it is sure to get some laughs when I retell it, especially the part about the bullet "coasting". Just my two cents.

 

[LME]

How do you figure out or measure where the "powder burned out"? What is so special about the "last two inches" of the barrel regarding accuracy? I think your "excellent shooter" is full of it! This is ,however, the first I've heard this "theory" & it is sure to get some laughs when I retell it, especially the part about the bullet "coasting". Just my two cents.

I learned a lot after I added some years to my life. One of the things I learned is strange things occur in life that have no rational? I listen to everyone and every now and then learn something new. As I said , I don't know?

 

[Sonny from Vincennes]

I have used a chronograph along with weighed powder charges and careful loading procedure to determine the best velocity. Most of the time the velocity will build up to a point and powder charges after that flatten out and sometimes go down slightly. This is called the laws of diminishing returns. This test works very good but one MUST be careful in the loading procedure to keep the variables at a minimum.
Good luck.

 

[Greg Y]

There's a great book by Harold Vaughn titled "rifle accuracy facts" that explains many of the mysteries in detail.

Vaughn was a scientist at NASA and had strain gauges set up everywhere and measured everything in incredible detail.

 

[Uncle Miltie]

The most accurate muzzle loaders ever made had barrels under 30 inches in length.

 

[Greg Y]

The most accurate muzzle loaders ever made had barrels under 30 inches in length.

There's lots of evidence to support that. If length increases stiffness has to increase exponentially and consistent harmonics become very difficult to reproduce.

 

[Felonious]

First off, welcome to the forum from Western North Carolina.

As far a determining percentage increase (guessing you are looking at velocity) in various barrel lengths, actual range time with a chronograph is the best method, although programs are out there that make calculations, but believe you would want to confirm their predictions. There are variables besides barrel length, things like powder manufacturer and granulation, roundball vs conical for example. Below is a link to a program (@chorizo was the most recent to post the link) that I found to be relatively close on velocities with a limited number of loads tested. Maybe a good starting point.
https://www.p-max.uk/cgi-bin/black_powder.cgi

That link you provided is incredibly useful for load development. For anyone reading this who hasn't checked it out, please do. I played with it for less than 5 minutes and learned a whole lot.

 

[Boomerang]

What is weird is that a lot of rifles have two different loads that are the most accurate. One at a heavier charge and one at a light charge.

 

[LME]

There's lots of evidence to support that. If length increases stiffness has to increase exponentially and consistent harmonics become very difficult to reproduce.

With thick heavy barrels harmonics efecting accuracy is at a minimum. My target rifles barrels were massive and were consistant.

What is weird is that a lot of rifles have two different loads that are the most accurate. One at a heavier charge and one at a light charge.

Without changing the geomerty of the riflings how can be possible? I have found that once you find your heaviest load that is accurate you can go down and retain accuracy is this what you are saying?

 

[Boomerang]

With thick heavy barrels harmonics efecting accuracy is at a minimum. My target rifles barrels were massive and were consistant.

Without changing the geomerty of the riflings how can be possible? I have found that once you find your heaviest load that is accurate you can go down and retain accuracy is this what you are saying?

Yes. It's usually around half of your highest accurate load. In my .54 GPR, my most accurate load is 75gr. 3f and my next most accurate load is 35gr. 3f. I use the light load for squirrel hunting. If I remember right, 75 gr. gave me around 1500 fps and 35gr. got me around 800fps.

 

[Sonny from Vincennes]

When I do a velocity test, I try to have the standard deviation less than 10 ft/sec for ten shots. I reduce the maximum charge by 40 percent and then increased in ten percent increments. I have built this procedure over a period of years. I feel very confident in the results.

 

[Sonny from Vincennes]

I have found black powder is best used in longer barrel guns. The other powders will give different results. For me I just enjoy shooting and testing loads. I am too old to hunt anymore and enjoy the private range.
Good luck to everybody.

 

[DementedMindOfJac]

How do you figure out or measure where the "powder burned out"? What is so special about the "last two inches" of the barrel regarding accuracy? I think your "excellent shooter" is full of it! This is ,however, the first I've heard this "theory" & it is sure to get some laughs when I retell it, especially the part about the bullet "coasting". Just my two cents.

A friend of mine who's passed now did a lot of R&D on barrels, coatings and linings, among other things. One of the things he was telling me about just before he passed was about smoothbore high velocity barrels where only the last 2 1/2" to the crown was rifled. I don't know enough and I can't afford a 20mm antimat rifle to find out, but he was not a man known for just talkin'.

 

[SDSmlf]

One of the things he was telling me about just before he passed was about smoothbore high velocity barrels where only the last 2 1/2" to the crown was rifled.

Sounds like modern rifled choke tubes intended to stabilize slugs fired out of shotguns.