Barrel length vs velocity

[lyle2231]

You are overloading your cases…period.

Cheers.

Thanks for your reply.

 

[Mike Matteson]

Please explain HOW this has ANYTHING to do with barrel LENGTH in your mind…because I CAN tell you what 'I' think is happening and it has nothing to do with barrel length…

Cheers.

I guess you didn't realize it's a Hollywood rifle. That explains everything!

 

[lyle2231]

I guess you didn't realize it's a Hollywood rifle. That explains everything!

Huh?..

 

[Damage Inc.]

Thanks for your reply. My curiosity is pressure curve compared to barrel length.

Pressure curve will be the same, but muzzle pressure will be different…. because the muzzle is in a different place on the curve when you shorten the barrel.

 

[lancetkenyon]

I have never researched pressure curves.

But here is my uneducated opinion.
I would think pressure curve has variations due to:
Powder selection
Powder charge weight and accuracy of charge weight
Powder burn rate
Case capacity
Case design
Brass quality
Projectile used
Chamber dimensions
Throat/lead design
Groove count and design
Barrel bore dimensions
Ambient temperature/barrel temperature

We all know longer barrels produce more velocity per inch.

I think most cartridges (.223 Wylde and 6BR for sure) have full burn within the barrel at reasonable lengths (16"+). So the only pressure curve variations would only be after the powder has fully burned and expanded gasses.

Just my thought process.

 

[lyle2231]

Pressure curve will be the same, but muzzle pressure will be different…. because the muzzle is in a different place on the curve when you shorten the barrel.

I've noticed about 200 fps slower in the 18" upper when compared to the 20" upper.

 

[lyle2231]

I have never researched pressure curves.

But here is my uneducated opinion.
I would think pressure curve has variations due to:
Powder selection
Powder charge weight and accuracy of charge weight
Powder burn rate
Case capacity
Case design
Brass quality
Projectile used
Chamber dimensions
Throat/lead design
Groove count and design
Barrel bore dimensions
Ambient temperature/barrel temperature

We all know longer barrels produce more velocity per inch.

I think most cartridges (.223 Wylde and 6BR for sure) have full burn within the barrel at reasonable lengths (16"+). So the only pressure curve variations would only be after the powder has fully burned and expanded gasses.

Just my thought process.

Thanks!

 

[lyle2231]

I have never researched pressure curves.

But here is my uneducated opinion.
I would think pressure curve has variations due to:
Powder selection
Powder charge weight and accuracy of charge weight
Powder burn rate
Case capacity
Case design
Brass quality
Projectile used
Chamber dimensions
Throat/lead design
Groove count and design
Barrel bore dimensions
Ambient temperature/barrel temperature

We all know longer barrels produce more velocity per inch.

I think most cartridges (.223 Wylde and 6BR for sure) have full burn within the barrel at reasonable lengths (16"+). So the only pressure curve variations would only be after the powder has fully burned and expanded gasses.

Just my thought process.

With my 18" upper it trends towards a faster propellant and slightly lighter bullet. Also likes the higher end of the bracket.

 

[lancetkenyon]

I've noticed about 200 fps slower in the 18" upper when compared to the 20" upper.

Still comparing two different barrels. I have even seen weird things when comparing same length barrels. Sometimes up to 100+ fps between same-length barrels.

No two barrels will be exactly the same.

I had a 26" Proof 6.5SS that would pressure up about 2.4gr lower charge weight than a 20" 6.5SS. So final max loads were nearly the same velocity, just due to the 20" being able to take more powder.

 

[Damage Inc.]

I've noticed about 200 fps slower in the 18" upper when compared to the 20200 fps loss in 2" is crazy. Should be more like 40-60

Then something is amiss. A 200 fps delta in 2" of barrel is excessive.

 

[lyle2231]

I have never researched pressure curves.

But here is my uneducated opinion.
I would think pressure curve has variations due to:
Powder selection
Powder charge weight and accuracy of charge weight
Powder burn rate
Case capacity
Case design
Brass quality
Projectile used
Chamber dimensions
Throat/lead design
Groove count and design
Barrel bore dimensions
Ambient temperature/barrel temperature

We all know longer barrels produce more velocity per inch.

I think most cartridges (.223 Wylde and 6BR for sure) have full burn within the barrel at reasonable lengths (16"+). So the only pressure curve variations would only be after the powder has fully burned and expanded gasses.

Just my thought process.

I've read over on Accurate Shooter about the 6Br where a fellow stated the 6Br w/30 grains of Varget. Was "the" load. I get to 27gr's and that is about maxed out. I've tried variations in OAL.

 

[lancetkenyon]

I've read over on Accurate Shooter about the 6Br where a fellow stated the 6Br w/30 grains of Varget. Was "the" load. I get to 27gr's and that is about maxed out. I've tried variations in OAL.

This is in a bolt action, correct?
What barrel? You could very well have a tight spot that is causing early pressure. I have seen it a few times.

Just because a load works for one rifle, does not mean it will in another.

Too many people think online information is gospel.

 

[Doom2]

Barrel length has no effect on peak pressure. As for comparing pressure between two different cartridges/calibers with different loads the pressure will be different.

 

[lyle2231]

This is in a bolt action, correct?
What barrel? You could very well have a tight spot that is causing early pressure. I have seen it a few times.

Just because a load works for one rifle, does not mean it will in another.

Too many people think online information is gospel.

REM 700 with a Brux barrel 1/8 .