Which is most detrimental to Barrel life and why?

[6BRA]

1.) Pressure- max/mid/low pressure loads. Quickloads, and or Reloading manual, or actual real pressure signs. Charge weight variance. How does pressure effect barrel life?

2.) Powder type- single base / double base. Fast burning or slower burning powders. Only about a 350 deg difference in chamber temps according to Quick loads.....3700 to 4050 deg.

3.) In line with question 2, the 95 percent burn rate. Less than 10 inches/ greater than 10 inches.

A powder that burns 95 percent, in say 15 to 20 inches of barrel vs 8 to 10 inches of barrel?

Slower burning powders are significantly greater than 10 inches at 95 percent burn. H4350 is an example. How important is this? How do 2 and 3 effect barrel life?

4.) What do you look for when trying to achieve maximum performance/ Small groups/ long barrel life?
Is it just luck for all of these to come together occasionally? What is the difference in a 1000 round Barrel vs a 4000 round barrel?

 

[K22]

Heat - that's what the experts tell me.

Barrels are consumables if you shoot as much as I do so I don't stress out about barrel life. I do not engage in sustained fire sequences which can cause a lot of heat to build quickly and erode the throat area. However, the reason I use this shooting style is not for barrel preservation, but because the cold / cool barrel shots are the one most significant in my discipline - eastern groundhog varmint / predator hunting.

As far as loads, I use the load that gives me the best precision without regards to barrel life issues. For the last 20 years or so I've use stick powders exclusively since in my experience these are more stable in the field and less sensitive to lot variations than ball powders.

Over bore cartridges are notorious for short barrel life but if you have a need for and have the skill to take advantage of the superior ballistics these cartridges offer, then by all means you should choose that cartridge regardless of barrel life considerations. For example, the 22 250 is a terrific varmint cartridge for shots beyond 300 yards. However, it can be hard on barrels but so what, the idea is to make a humane first shot.

I treat firearms as tools, to be used but not abused. So, to answer your question, your discipline will dictate the rate of fire required and the precision required. These should be the overriding considerations, not barrel life. Of course, you want to use safe and effective cleaning procedures to maximize barrel precision life and not unnecessarily overheat your barrel.

A shooter who wears out a barrel is doing what he should be doing, shooting a lot and having fun.

 

[urbanrifleman]

The flamethrower coming out of the case. The larger and more concentrated the flame, and the hotter and longer the duration, the more it tears up the steel.

 

[farmerjohn]

1.) Pressure- max/mid/low pressure loads. Quickloads, and or Reloading manual, or actual real pressure signs. Charge weight variance. How does pressure effect barrel life?

2.) Powder type- single base / double base. Fast burning or slower burning powders. Only about a 350 deg difference in chamber temps according to Quick loads.....3700 to 4050 deg.

3.) In line with question 2, the 95 percent burn rate. Less than 10 inches/ greater than 10 inches.

A powder that burns 95 percent, in say 15 to 20 inches of barrel vs 8 to 10 inches of barrel?

Slower burning powders are significantly greater than 10 inches at 95 percent burn. H4350 is an example. How important is this? How do 2 and 3 effect barrel life?

4.) What do you look for when trying to achieve maximum performance/ Small groups/ long barrel life?
Is it just luck for all of these to come together occasionally? What is the difference in a 1000 round Barrel vs a 4000 round barrel?

Like @K22 says, heat and lack of proper cleaning, any door gunner on a Huey from the Vietnam era can you just how quickly heat can get a barrel, I've proven the same thing to my self on a much smaller scale shooting prairie dogs... John

 

[bugman]

You are forgetting rate of fire.....just ask the prairie dog shooters , or guys that shoot 25 siters before their record rounds.

 

[Chaotik]

You are forgetting rate of fire.....just ask the prairie dog shooters , or guys that shoot 25 siters before their record rounds.

I have ruined barrels shooting too many sighters too fast....

 

[BoydAllen]

A lot of fellows think that as long as the outside of the barrel is not too hot (whatever that means to them) that they are OK. The truth is that it takes a while for heat to make its way to the outside of a barrel and so. Particularly with heavy contours, you can have more heat in the throat build up than you may realize.

OMO the expansion ratio of the caliber (capacity of case relative to diameter of bore) combined with rate of fire are the biggest determiners of barrel life. You can also see differences based on how hotly a powder burns, and even the shape of the grains.

Back in the day when I was planning my first rifle for shooting groups at the range, I looked around for a cartridge that was very accurate and seemed to be relatively easy on barrels and built a tight neck chamber .222. It was a good choice. These days, a straight 6BR would be one to consider. If you don't mind dealing with a wildcat, the .30 BR is somewhere near the top of the list (by quite a bit) for acccurate cartridges with long barrel life.

 

[gunsandgunsmithing]

Heat and pressure are the big factors. Heat is obvious and is generally a byproduct of pressure. But pressure alone is over simplified. Every time we pull the trigger the barrel swells just a little bit. I believe this is a bigger factor than most realize. It works hardens the surface, along with heat and contributes to what we call fire cracking, which creates a rough surface that absorbs more heat, compounding the issue. Bottom line, lower pressure creates less heat and less wear, overall but for more reasons than temp alone. Ultimately, if bbl life is the goal with a given cartridge, reducing loads will help more than just about anything. As Boyd said too, expansion ratio plays a huge role if using a different cartridge altogether is an option. It's tough to find many that will outlast a 30BR or 30 Major.

 

[6BRA]

So almost every answer so far, has to do with heat. Would it be fair to say, that a powder that burns 95 percent for a given caliber in 8 to 9 inchs of Bbl, is going exert more heat in a smaller space, than a powder that burns 95 percent in 14 inches of bbl? or Even a powder that takes it to 21 inches for 95 percent burn? Doesnt this spread the heat over a larger volume of bbl. Reducing wear?

 

[gunsandgunsmithing]

So almost every answer so far, has to do with heat. Would it be fair to say, that a powder that burns 95 percent for a given caliber in 8 to 9 inchs of Bbl, is going exert more heat in a smaller space, than a powder that burns 95 percent in 14 inches of bbl? or Even a powder that takes it to 21 inches for 95 percent burn? Doesnt this spread the heat over a larger volume of bbl. Reducing wear?

Splitting hairs but faster powders do the same work in less time than slower ones. So yes, the heat is gone sooner and will, to an extent, do less damage to the bbl. Again, splitting hairs. If your goal is long bbl life, measurably better, a different cartridge is the first thing to consider...then reducing loads. The rest gets lost in the noise. Some bbls last longer than others.

 

[762plinker]

The flamethrower coming out of the case. The larger and more concentrated the flame, and the hotter and longer the duration, the more it tears up the steel.

well sort of ...
big case narrow neck is high velocity gas with temp and pressure....
drop the gas velocity and the bbl lasts longer
look at a 30 br

 

[6BRA]

If a person has Quickloads, and they want to start load development and have every powder under the Sun, available. Would you start with the proven loads, which are typically hotter/faster burning powders or would you start on the slower burning powders and work up? Obviously, case capacity would limit how slow you can go.
H4350 is borderline...real borderline too slow for the 6br. There is alot of talk about this powder being used for the very reasons I had mentioned. 21 inch/95 percent burn. Moving up there is RL17/RL16/RL15.5/RL 15/Vargeet.....and up the ladder up to the top H4895/ 8208 etc. Where does one start? RL 17 will yield high velocity with a middle pressure load.

 

[6BRA]

well sort of ...
big case narrow neck is high velocity gas with temp and pressure....
drop the gas velocity and the bbl lasts longer
look at a 30 br

Do the Ackley Improved versions slow the velocity down? I thought I read the 6BRA doesn't eat throats anywhere near as bad.

 

[gunsandgunsmithing]

If a person has Quickloads, and they want to start load development and have every powder under the Sun, available. Would you start with the proven loads, which are typically hotter/faster burning powders or would you start on the slower burning powders and work up? Obviously, case capacity would limit how slow you can go.
H4350 is borderline...real borderline too slow for the 6br. There is alot of talk about this powder being used for the very reasons I had mentioned. 21 inch/95 percent burn. Moving up there is RL17/RL16/RL15.5/RL 15/Vargeet.....and up the ladder up to the top H4895/ 8208 etc. Where does one start? RL 17 will yield high velocity with a middle pressure load.

I load strictly for accuracy. Often, possibly due in part to lower muzzle pressures, I find faster powders for a given application work best. I think throat design might be worth playing with in regard to bbl life.

 

[Straightshooter1]

I'd say, all the above that's been mentioned effects barrel life as it all works in concert. To choose a single thing that's "most detrimental to barrel life" is apparently heat. And that's why I keep track of barrel temperature when firing and keeping my rate of fire reasonable.

Looking close at the chart below might help with an idea about that:

 

[6BRA]

I'd say, all the above that's been mentioned effects barrel life as it all works in concert. To choose a single thing that's "most detrimental to barrel life" is apparently heat. And that's why I keep track of barrel temperature when firing and keeping my rate of fire reasonable.

Looking close at the chart below might help with an idea about that:

View attachment 1434626

what is bore capacity charge weight? Say on 6mm...28? The others are estimated bbl life number of firings based on powder charge?

 

[Big Mc]

1.) Pressure- max/mid/low pressure loads. Quickloads, and or Reloading manual, or actual real pressure signs. Charge weight variance. How does pressure effect barrel life?

2.) Powder type- single base / double base. Fast burning or slower burning powders. Only about a 350 deg difference in chamber temps according to Quick loads.....3700 to 4050 deg.

3.) In line with question 2, the 95 percent burn rate. Less than 10 inches/ greater than 10 inches.

A powder that burns 95 percent, in say 15 to 20 inches of barrel vs 8 to 10 inches of barrel?

Slower burning powders are significantly greater than 10 inches at 95 percent burn. H4350 is an example. How important is this? How do 2 and 3 effect barrel life?

4.) What do you look for when trying to achieve maximum performance/ Small groups/ long barrel life?
Is it just luck for all of these to come together occasionally? What is the difference in a 1000 round Barrel vs a 4000 round barrel?

What K22 said Tommy Mc

 

[Straightshooter1]

what is bore capacity charge weight? Say on 6mm...28?

If I recall correctly, it's simply the area of the bore diameter used for the calculations.

The others are estimated bbl life number of firings based on powder charge?

Yes.

 

[Evan]

Talking from a competitive setting, and in particular long range benchrest, I think it is fairly uncontroversial to suggest that there is no cheating the physics. You need a certain performance envelope to be highly competitive and combinations that fall within that envelope all end up with vastly similar barrel life. A 6BRA does not have an appreciably longer barrel life than a 300 SAUM when used for 1000yd becnhrest matches and load development.

Another example: I ran my first 6.5x47 barrel hard. I loaded the 153.5gn Berger to 2850fps. That barrel lost its competitive edge at ~900 rounds. I believe that is quite similar barrel life to a 6.5x284 which achieves the same speeds with more powder and less pressure. My second barrel, I ran a much more pedestrian 2820fps with a 133gn Vapor Trail and saw much reduced barrel wear but couldn't get the performance out of it that I needed to be competitive.

 

[Rsadams]

Heat....