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Range Report What makes a barrel prefer one ammo brand or grain ?

CygnusX1

CygnusX1

Sergeant of the Hide
Full Member
Minuteman
Dec 22, 2019
130
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Quebec, Canada
#1
I could not find an existing tread on this so here goes:

Assume we have a rifle chambered in 6.5 Creed.
All manufactured 6.5mm Creed ammo will have cases and bullet diameters the same. Thats why they are called 6.5 creed.

The differences come in the grain of the bullet and the powder used.

So what makes a barell prefer one grain or faster/slower powder ?

I see a lot of treads in here from shooters trying diffrrent brands with different grains so this seems to be somewhat of a mistery......

Thanks for your inputs
 
#3
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#4
Voodoo Magic. Seriously though, if anyone actually knew 100% why things are the way they are they'd be rich beyond belief. Applied Ballistics is probably the closest you'll get. There seems to be some things that just generally work and things that generally don't. For example, the Sierra Match Kings usually aren't jump sensitive while the Berger VLD's are. So many variables that are impossible to isolate, you could drive a man insane just thinking about it.
 
#8
SD carpenter said:
It has to do with barrel harmonics? Not all metal is made exactly the same?
[/QUote

I once read that longuer barrels (say 26 inches) resonate more than shorter barrels (say 20 inches)...(assuming same thickness and metal).

But all bullets will make barrels resonate.
So longuer barrels require lighter grain bullets ??

Still scratching my head....
Click to expand...
 
#9
CygnusX1 said:
I could not find an existing tread on this so here goes:

Assume we have a rifle chambered in 6.5 Creed.
All manufactured 6.5mm Creed ammo will have cases and bullet diameters the same. Thats why they are called 6.5 creed.

The differences come in the grain of the bullet and the powder used.

So what makes a barell prefer one grain or faster/slower powder ?

I see a lot of treads in here from shooters trying diffrrent brands with different grains so this seems to be somewhat of a mistery......

Thanks for your inputs
Click to expand...

Who the fuck knows? More importantly, who the fuck cares?

I don't waste my time pondering things I have no control over. if a particular load won't shoot I change it till it will.
 
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#11
It has to do with the freebore, leade angle, barrel length, rifling twist rate, barrel land and groove dimensions and tolerances kept during the manufacturing, barrel harmonics as the controlled explosion occurs..... and more variables..... and how the particular bullet interacts with all that stuff. Some barrels and manufactures make their assorted variables shoot the majority of factory ammo very well, like half-moa. Some better than others. Accuracy International and a handful of other manufacturers come to mind.

Then you have other chambers that are throated for a specific round like the military's 300 WinMag sniper rifles that are spec'd for exactly one particular type of ammunition, the Mk 248 Mod 0 and Mod 1.

I know I didn't answer your question, but I wanted to just kinda throw a bunch of spaghetti at your brain and hopefully some will stick and poke you to research deeper on internal and external ballistics.


Or, conversely, you can do what this fuckin' guy suggests ?? sometimes it's better to streamline the process

???
308pirate said:
Who the fuck knows? More importantly, who the fuck cares?

I don't waste my time pondering things I have no control over. if a particular load won't shoot I change it till it will.
Click to expand...
 
#13
clcustom1911 said:
It has to do with the freebore, leade angle, barrel length, rifling twist rate, barrel land and groove dimensions and tolerances kept during the manufacturing, barrel harmonics as the controlled explosion occurs..... and more variables..... and how the particular bullet interacts with all that stuff. Some barrels and manufactures make their assorted variables shoot the majority of factory ammo very well, like half-moa. Some better than others. Accuracy International and a handful of other manufacturers come to mind.

Then you have other chambers that are throated for a specific round like the military's 300 WinMag sniper rifles that are spec'd for exactly one particular type of ammunition, the Mk 248 Mod 0 and Mod 1.

I know I didn't answer your question, but I wanted to just kinds throw a bunch of spaghetti at your brain and hopefully some will stick and poke you to research deeper on internal and external ballistics.


Or, conversely, you can do what this fuckin' guy suggests ?? sometimes it's better to streamline the process

???
Click to expand...
CygnusX1 said:
I can see this dampening resonances
Click to expand...
Although there is no quick and easy answer, I see the variables in the barrel's manufacturing as you enumerate them. Every single one of them can and will affect the bullet's path inside the barrel

This will stick !
Thank you !
 

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#14
I totally understand why tuning a load to barrel harmonics works.

What makes no damn sense to me is how for example, you might have a 105gr bullet from company A shoot great at 3000 fps. But then, if you switch to a different 105gr bullet from company B it can shoot like dogshit, even if you tweak the powder charge until you achieve the same 3000 fps. Obviously bullet brands must be very different from each other.
 
#15
No taboo or secret rules
And it wasnt meant mean.... you are new and we see alot of new people ask questions like this before they do the research.

Atleast you asked so kudos on that.


You asked a question because you dont know why but you also made a statement that while not incorrect is also variable.

A barrel has no preference to "brand"
A barrel has no preference to "grain"

All 6.5 creedmor ammo is not the same. As a generality there are things very close but not the same.

The only real answer is that every discussion on accuracy, loads, barrels, bullets, chassis, weather, and more are the answer to your question.

The simple answer is as others have said largely a function of harmonics of the system.

But that leads to more questions.
 
#16
Namekagon said:
I totally understand why tuning a load to barrel harmonics works.

What makes no damn sense to me is how for example, you might have a 105gr bullet from company A shoot great at 3000 fps. But then, if you switch to a different 105gr bullet from company B it can shoot like dogshit, even if you tweak the powder charge until you achieve the same 3000 fps. Obviously bullet brands must be very different from each other.
Click to expand...

If the weight, bearing surface area, ogive profile and overall bullet length are identical then there should be little to no change, within limits.

Change any one of those variables and you can upset the balance. No surprise here: There's a big difference between loading for a tangent versus secant ogive, not only with external ballistics but also the internal (case capacity, initiation pressure, freebore, etc).

 
#17
1moaoff said:
No taboo or secret rules
And it wasnt meant mean.... you are new and we see alot of new people ask questions like this before they do the research.

Atleast you asked so kudos on that.


You asked a question because you dont know why but you also made a statement that while not incorrect is also variable.

A barrel has no preference to "brand"
A barrel has no preference to "grain"

All 6.5 creedmor ammo is not the same. As a generality there are things very close but not the same.

The only real answer is that every discussion on accuracy, loads, barrels, bullets, chassis, weather, and more are the answer to your question.

The simple answer is as others have said largely a function of harmonics of the system.

But that leads to more questions.
Click to expand...

"Harmonics"
....and this is why reloaders go to great lenghts to get a tuned load with consistency for each cartridge to hit those harmonics just right... to get both Accuracy and Precision

I'm getting the big picture !

Shooting is fun but improving our scores involves many topics and discipline.
And that's part of the fun too (y)

Thank you !
 
#18
AIAW said:
If the weight, bearing surface area, ogive profile and overall bullet length are identical then there should be little to no change, within limits.

Change any one of those variables and you can upset the balance. No surprise here: There's a big difference between loading for a tangent versus secant ogive, not only with external ballistics but also the internal (case capacity, initiation pressure, freebore, etc).

Click to expand...

Thanks for the link AIAW !
This is all new to me and I ordered a book from the same author (y)
 

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#19
CygnusX1 said:
Thanks for the link AIAW !
This is all new to me and I ordered a book from the same author (y)
Click to expand...
There is lots of reading on their website that you can read too https://appliedballisticsllc.com/education/

In the education section you can scroll to the left and see all sorts of papers to read, paper to the right are more recent and bullet profiles
 
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#20
spife7980 said:
There is lots of reading on their website that you can read too https://appliedballisticsllc.com/education/

In the education section you can scroll to the left and see all sorts of papers to read, paper to the right are more recent and bullet profiles
Click to expand...
Wow !
You're not kidding !!
Tons of reading material in that website.....perhaps much of the content of his book I just ordered :p

Thanks for the tip ! (y)
 
#24
There's a shit ton of physics involved that we've lacked the instruments to measure accurately. So, the only other way was trial and error with meticulous data. But since we know results but not really the why, we continue to test.

Instrumentation, stout computing power, and highly precise and repeatable manufacturing are placing us on the precipice of a renaissance in ballistics. The myths and wive's tales will soon give way to extremely precise data which will lead to cheap and highly accurate ammo and guns/actions/barrels. Vudoo is an example of that and what's to come.
 
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