Barrel life

[GoatLD259]

Good Afternoon Hide

I stumbled upon a video on YouTube that speaks about Barrel life. He talks about the main reasons that wear a barrel out. A secondary reason that wears barrels out he mentions is internal cartridge pressure. He uses examples how a 7mm Mauser is more efficient than a 300 Win Mag. Citing that internal pressure from n the 7mm is 51000 psi with a velocity of 3300. The 300 Win mag has an internal pressure of over 60,000, but with a velocity of 3100. He says the 7mm is more efficient. But, I’m not wrapping my head around how this inefficiency affects barrel life? He brings up that necked down rounds are less efficient, and will have less pressure to move the round out.

Please help.

Here is the link.


Goat

 

[Newbie2020]

My feeble understanding of why various cartridges are more or less "overbore", is that a greater powder charge relative to bullet weight results in more unexpended powder burning as the bullet enters then exits the chamber throat, resulting in a huge amount of heat in the throat leading to throat erosion.

I assume the "efficiency" he's referring to is getting a similar sized (not identical) projectile to greater velocity using less powder makes the 7mauser more efficient and less overbore, leading to much slower throat erosion.

6cm is more "overbore" than 6.5cm because roughly the same powder charge is pushing a 25% lighter pill down the tube resulting in more fire entering the throat for the 6cm.

 

[GoatLD259]

My feeble understanding of why various cartridges are more or less "overbore", is that a greater powder charge relative to bullet weight results in more unexpended powder burning as the bullet enters then exits the chamber throat, resulting in a huge amount of heat in the throat leading to throat erosion.

I assume the "efficiency" he's referring to is getting a similar sized (not identical) projectile to greater velocity using less powder makes the 7mauser more efficient and less overbore, leading to much slower throat erosion.

6cm is more "overbore" than 6.5cm because roughly the same powder charge is pushing a 25% lighter pill down the tube resulting in more fire entering the throat for the 6cm.

He mentions to that a necked down round will have less pressure than a case that is more straight. But then points of the internal pressures of the 7mm vs 300 Win Mag. So do less efficient rounds not burn all the powder, resulting in it getting into the barrel and causing erosion?

 

[supercorndogs]

51000PSI should have more barrel life than 60,000psi. Less powder relative to bore size, will wear out the barrel slower. I.E a 22/243AI burns a lot of powder relative to its bore size. Barrel life is meh.

 

[918v]

Good Afternoon Hide

I stumbled upon a video on YouTube that speaks about Barrel life. He talks about the main reasons that wear a barrel out. A secondary reason that wears barrels out he mentions is internal cartridge pressure. He uses examples how a 7mm Mauser is more efficient than a 300 Win Mag. Citing that internal pressure from n the 7mm is 51000 psi with a velocity of 3300. The 300 Win mag has an internal pressure of over 60,000, but with a velocity of 3100.

That’s not what he said. He compared the 7x57 Mauser to a 6mm Remington. They both have the same parent case but the 6 is 1mm smaller than the 7. The 7x57 is more efficient with the same weight bullet.

 

[Mr Tibbs]

From what i understand one thing that effects barrel life is pressure, the overbore rounds like the 22-250 Remington , 243 Winchester, 257 Roberts, 260 Remington, 264 Winchester Magnum,7MM Remington Magnum just to name a few . All these rounds perform better with a heavier bullet weights . For instance a lot of hand loaders like to use a 55 Gr bullet in the 243 Winchester . A steady diet of 55 Grainer’s at 4000 FPS with those light bullets will burn a barrel out faster than say a 100 Gr going @2960 FPS or higher .

 

[Steel head]

From what i understand one thing that effects barrel life is pressure, the overbore rounds like the 22-250 Remington , 243 Winchester, 257 Roberts, 260 Remington, 264 Winchester Magnum,7MM Remington Magnum just to name a few . All these rounds perform better with a heavier bullet weights . For instance a lot of hand loaders like to use a 55 Gr bullet in the 243 Winchester . A steady diet of 55 Grainer’s at 4000 FPS with those light bullets will burn a barrel out faster than say a 100 Gr going @2960 FPS or higher .

It not just pressure

run a 6BR and a 243 at the same pressure and see which one wears out first.
The amount of powder burning through the bore size is a huge factor.

 

[A&8's]

Gunblue is very very stuck in 1950 way of thinking on 90% of his videos. And just plain wrong on the other 10%. He’s too hard headed to accept modern technology. I can’t force myself to watch his videos, anymore.

Heat, not pressure is the killer of a barrel. That’s why barrels that get “shot out” are from throat erosion. That’s why people “chase the lands.”

 

[Dthomas3523]

Meh, unless it someone with a related education or is an internal ballistics SME, I wouldn’t pay much attention.

At least half of this stuff in this side of the industry is theory without any real knowledge behind it.

 

[FLIGHT762]

Gunblue is very very stuck in 1950 way of thinking on 90% of his videos. And just plain wrong on the other 10%.

I found this true in some of his videos and I made a comment in one of his videos where he responded back and was quick to discount another observation backed by facts.

I got tired of his videos and stopped watching. He reminded me of dealing with hard headed command staff in my L/E career. When I found out he was a retired Captain in L/E, I laughed.

 

[Mr Tibbs]

It not just pressure

run a 6BR and a 243 at the same pressure and see which one wears out first.
The amount of powder burning through the bore size is a huge factor.

Steel head you’re correct I forgot about the amount of powder , and heat not letting the barrel cool down enough in between strings, will also send a barrel to a early grave .