just something to try, debunking a barrel life myth

[wingnut]

I'd like to know how Hatcher reached these conclusions also.

Ask Ken Howell. He and Homer Powley were buddies.

burn up a few barrels and tell me how it goes.

I've fried a few barrels. One stainless match, at 500 rounds, had 2 inches of rifling gone at the throat.

 

[RiverRider]

When folks start getting defensive and taking it personally, time to bow out.

 

[Guy Miner]

"I've fried a few barrels. One stainless match, at 500 rounds, had 2 inches of rifling gone at the throat."

Wow! What cartridge? What were the circumstances?

One of the reasons most of my center fire rifle shooting is done with the .308 Win is that I typically get 5,000+ rounds of accurate barrel life - much of that is at NRA slow-fire prone matches. Even "slow fire" the barrels get pretty warm after 20+ shots in about eight or ten minutes.

Regards, Guy

 

[Ridge_Runner]

how can you argue the point if you fried a barrel with 500 rounds? did you figure out why?
why does a guy burn a barrel out in 500 rounds, and someone else gets 1200 0r more out of the same barrel with the same chamber?

We know you can burn a barrel out in a day using a high energy cartridge on a prairie dog town with say 600 rounds? correct?
so does that mean 600 rounds is the max life of that barrel chambered in that cartridge? is there more energy expelled with those 600 rounds than there are in 600 rounds fired over a period of years?
so maybe heat has something to do with it? and I've proven to myself that shooting ball powder results in less barrel heat that extruded powder, and is it not possible that the shape and size of the powder granules could be less abrasive on the throat under firing tempatures?
RR

 

[atmoshpere]

Ridge Runner: It seems through some of your observations, we can draw a few conclusions. Your example of the prairie dog hunt, I think, illustrates a good point in the barrel erosion topic that I'm sure many here already know but I'll post anyways for the sake of conversation. I seem to remember from chemistry that there is a strong connection between temperature and reaction speed in chemical processes. So I'm thinking that even though your six hundred rounds have the same energy whether fired over 2 years or 8 hours, the resultant barrel heat accumulation is much greater when fired in a small window, which in turn would accelerate erosion further. Simplified: It would seem that a high power load fired down an already HOT barrel will do more dmg than the same load fired from a cold barrel bacause if the differences of the physical properties of metal at different temperatures.

I am curious to know if the peak temps reached by different types of powder are higher than both powder's flame temp, does flame temp really matter? Is flame temp just the temp it takes to ignite the powder, or am I misunderstanding that?

 

[Guy Miner]

There was a guy on another forum promoting a cartridge he called the 6mm Competition Match or something like that. Essentially it was a .243 with a sharper shoulder as I recall. Could be wrong.

He was talking it up for increased barrel life, by using a combination of slow burning powder and a very specific cleaning program, all aimed at reducing throat erosion. This concept seemed to have some merit - but I never bit and ordered one of his 6mm barrels/chambers/reamers.

I'm sure no expert, but looking through a bore scope at a heavily "eroded" throat reveals checkering, almost like an alligator skin, inside of high-use barrels. Almost all of it in the throat area.

Slow fire barrels, which also get hot, don't seem to end up "shot out" nearly as fast as barrels used in rapid fire competition, which get scorching hot, as do high-use varmint rifle barrels used for prairie dog & sage rat extermination, when literally hundreds of rounds a day might be fired.

The intense, smaller bore cartridges which are increasingly popular for competition these days also have a well earned reputation for rapidly eroding the barrel throats and ruining barrels pretty quickly.

It was interesting to note that the guys running the 6.5-284's for long range competition enjoyed a considerable ballistic advantage over the guys running .308's, but had to replace their barrels much more frequently. On the order of every 1,000 - 1,500 rounds rather than 4,500+ rounds. I long since concluded that barrels are expendable - just like tires and brakes - even the good ones wear out eventually.

Just random thoughts kicking around, generated by the barrel life discussion.

Time to wake up my sleepy kid and go fishing. Regards, Guy

 

[Ridge_Runner]

Ridge Runner: It seems through some of your observations, we can draw a few conclusions. Your example of the prairie dog hunt, I think, illustrates a good point in the barrel erosion topic that I'm sure many here already know but I'll post anyways for the sake of conversation. I seem to remember from chemistry that there is a strong connection between temperature and reaction speed in chemical processes. So I'm thinking that even though your six hundred rounds have the same energy whether fired over 2 years or 8 hours, the resultant barrel heat accumulation is much greater when fired in a small window, which in turn would accelerate erosion further. Simplified: It would seem that a high power load fired down an already HOT barrel will do more dmg than the same load fired from a cold barrel bacause if the differences of the physical properties of metal at different temperatures.

I am curious to know if the peak temps reached by different types of powder are higher than both powder's flame temp, does flame temp really matter? Is flame temp just the temp it takes to ignite the powder, or am I misunderstanding that?

Now maybe I'm using the wrong term but its all I've ever heard but I'm referring to the burning temp where powder makes gas, I also realize that a smaller diameter from the same case is harder on barrels, as in the 264 winny compared to the 338, however I've known guys who shoot a .277 cartridge with around 120 gr capacity of H2o and have gotten right at 1K rounds before setback, some 7 mags don't last that long, why? I know these guys shoot ball powder, and they don't shoot the barrel hot, the same practice I stick with, As I've said before, I have 450 rounds downrange in my 7mm AM, I shoot a 160 AccuBond jammed .006 into the lands, running 3575 fps with 110 gr of WC872 since the beginning I would once in a while pull a bullet unloading an unfired round, to this day, with no changes to my seater die I still to this day occasionaly pull a bullet unloading an unfired round, so how bad is my throat eroding?
I'm looking to get 900 rounds at least from this barrel, how can I get this kind of barrel life when alot of folks who shoot a 7 mag don't do as well? if not from ball powder than what?
RR

 

[atmoshpere]

Now maybe I'm using the wrong term but its all I've ever heard but I'm referring to the burning temp where powder makes gas, <that makes sense> I also realize that a smaller diameter from the same case is harder on barrels, as in the 264 winny compared to the 338, <if they both operate under the same max pressure, is this then caused by the difference in velocity of the bullet travelling down the barrel?> however I've known guys who shoot a .277 cartridge with around 120 gr capacity of H2o and have gotten right at 1K rounds before setback, some 7 mags don't last that long, why? I know these guys shoot ball powder, and they don't shoot the barrel hot, the same practice I stick with, As I've said before, I have 450 rounds downrange in my 7mm AM, I shoot a 160 AccuBond jammed .006 into the lands, running 3575 fps with 110 gr of WC872 since the beginning I would once in a while pull a bullet unloading an unfired round, to this day, with no changes to my seater die I still to this day occasionaly pull a bullet unloading an unfired round, so how bad is my throat eroding?
I'm looking to get 900 rounds at least from this barrel, how can I get this kind of barrel life when alot of folks who shoot a 7 mag don't do as well? if not from ball powder than what? <how much effect do you think barrel stock metal makes? Do different barrel makers use different metals which have different hardnesses? I'm sure someone could staighten us out as to the intricacies of interior ballistics as it relates to barrel life :shock: Are ball powders double base? A flatter pressure curve along with lower flame temp sounds like it could make a significant difference...still curious as to wether temps at peak pressure are higher than the flame temp for a given powder, at which point I would think flame temp would become irrelevant, but I may be wrong. Looks like I have a new research project!> RR

 

[Ridge_Runner]

Now maybe I'm using the wrong term but its all I've ever heard but I'm referring to the burning temp where powder makes gas, <that makes sense> I also realize that a smaller diameter from the same case is harder on barrels, as in the 264 winny compared to the 338, <if they both operate under the same max pressure, is this then caused by the difference in velocity of the bullet travelling down the barrel?>

Its caused by 2 reasons 1) smaller bullets of the same capacity need more powder to hit the same pressures due to less resistance of a smaller bullet which causes 2) more hot gases going through a smaller diameter throat

however I've known guys who shoot a .277 cartridge with around 120 gr capacity of H2o and have gotten right at 1K rounds before setback, some 7 mags don't last that long, why? I know these guys shoot ball powder, and they don't shoot the barrel hot, the same practice I stick with, As I've said before, I have 450 rounds downrange in my 7mm AM, I shoot a 160 AccuBond jammed .006 into the lands, running 3575 fps with 110 gr of WC872 since the beginning I would once in a while pull a bullet unloading an unfired round, to this day, with no changes to my seater die I still to this day occasionaly pull a bullet unloading an unfired round, so how bad is my throat eroding?
I'm looking to get 900 rounds at least from this barrel, how can I get this kind of barrel life when alot of folks who shoot a 7 mag don't do as well? if not from ball powder than what? <how much effect do you think barrel stock metal makes? Do different barrel makers use different metals which have different hardnesses? I'm sure someone could staighten us out as to the intricacies of interior ballistics as it relates to barrel life :shock: Are ball powders double base?

most barrel makers use 416 or 440c stainless or chrome moly for the blued barrels, yes ball powders are double based

A flatter pressure curve along with lower flame temp sounds like it could make a significant difference...still curious as to wether temps at peak pressure are higher than the flame temp for a given powder, at which point I would think flame temp would become irrelevant, but I may be wrong. Looks like I have a new research project!> RR

RR