6.5 forever
Silver $$ Contributor
Seen a few posters saying they preferred the lower speed node citing less barrel wear. Does say 30 fps per shot really make a difference? Any testing to verify round counts?
How Does Bullet Velocity (hi/lo) Affect Barrel Wear
- Thread starter 6.5 forever
- Start date
Very complex topic. Any so-called answers you get here will be oversimplified. If you do some searching you will find a lot of interesting research from sources like the US Army based on research projects at the Aberdeen proving ground. Of course their most recent stuff is not released to the public domain yet but the older stuff is fun to read and think about. A fair amount of the Army stuff is focused on large caliber weapons but most if not all of the same principles should still apply.
6.5 forever
Silver $$ Contributor
And I shoot 6.5 CM, below military interests.
I am not expert but what some of them told me is that there are 3 things that cause barrel wear:
1. Heat
2. Friction (bullet drive down bore)
3. Erosion (for powder)
By a significantly large margin it is heat - excessive sustained fire sequences heating barrel is the biggest culprit since it changes the metallurgy of the interior bore.
There is another issue, depending on the expert consulted, improper cleaning.
1. Heat
2. Friction (bullet drive down bore)
3. Erosion (for powder)
By a significantly large margin it is heat - excessive sustained fire sequences heating barrel is the biggest culprit since it changes the metallurgy of the interior bore.
There is another issue, depending on the expert consulted, improper cleaning.
Whats benchrest 3 minutes between shots and it still depends alot on the temp. how much your barrel cools. Doug
Agree!
Here, around Phoenix AZ, summer time is a big challenge in keeping the barrel cool as it doesn't take long the the barrel to really heat up fast when the ambient temperatures are above 85°F. My rate of fire is really slowed down as I closely watch my barrel temperature when temps are in the 90's and above (watching my temperature strip mounted on the barrel just forward of chamber). And in those hot ambient temperature, it takes a while for my barrel cooler to cool it down enough to be able to get more than a few shot off before cooling down again. Like, when I see the temperature get to 122°F and approaching 131°F, I stop and let it cool down. When the ambient temperatures are 70°F and below, I don't have any real time lags do to barrel temperature as I'm not shooting rapid fire or any semi-auto. Not letting my barrel temperature get much above that 122° marks has worked well for me in giving me decent barrel life.
What really knocks your noodle when you're looking at 'extending' barrel life is to think about the fact that even with something like a slow .284 going 2740, which may extend an average competitive barrel to maybe 2000rds you have a total of less than 2 seconds cumulative bullet to barrel contact time for the competitive life of the barrel. So when someone asks me how long my barrels last, I say "oh about one and half seconds"
6.5 forever
Silver $$ Contributor
Based on responses, I'll go ahead and load to the more accurate higher velocity node.
jackieschmidt
Gold $$ Contributor
With my 30BR and 6 PPC, the only appreciable “wear” is the area just forward of the throat.
I set them back periodically and they keep shooting.
I set them back periodically and they keep shooting.
Old Navy
Gold $$ Contributor
And to cool it down.
urbanrifleman
Site $$ Sponsor
It's the flame throwing fire/cutting torch that is the culprit.
Bullets are soft. That's why the end of the barrel never seems to wear at all.
Of course, trying to make the bullet go faster is what makes the flame thrower go from low to high. So, the scorched earth in the throat is usually the result of speed addiction.
And the effect is not linear
Bullets are soft. That's why the end of the barrel never seems to wear at all.
Of course, trying to make the bullet go faster is what makes the flame thrower go from low to high. So, the scorched earth in the throat is usually the result of speed addiction.
And the effect is not linear
You nailed it!!! From Thermodynamics, the heat and pressure of hot gases is Plasma Energy!! Just like a plasma torch with burst of energy with a duration of micro seconds!!! Those micro seconds of plasma burst are accumulative!! Increasing the pressure, increases the heat!! All Firearms have a plasma torch inside the barrel!!!
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Your milage will vary. One rifle shooting the hot load in very short shot strings may get a longer total round count then the rifle that shoots the slower round if the rifle is fired in fast long shot strings.
I've seen 5.56 rifles shooting standard loads ruined after a few days at the range. I've seen 5.56 rifles shooting hot heavy weight handloads shooting for decades with round counts in the 5,000+ range still shooting well.
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I respectfully disagree with this comment - the gases are hot, yes, but they're not the fourth state of matter, plasma, as they are quite unlikely to be charged electrically.
The fourth state of matter is PLASTIC (ballistics gel, Jello, peanut butter, grease, waxes, pastes, etc), NOT PLASMA WHICH IS A HIGH ENERGY STATE OF MATTER! The sun is a very high density plasma!! The energy from plastic explosives is high energy plasma and can cut through metal like a knife!! Plasma energy can be nuclear (fission, fusion), physical chemical reactions (fire, gas torches, etc), electrical (plasma torch, arc welders, lighting, etc)!! Fire is classified plasma if it is hot and dense enough!!! In Thermodynamic, pressure and heat (energy) are directly proportional to each other in changing volume!!! The internal ballistics shows the high energy gas is so dense that it becomes a liquid high energy state!! PLASMA!!! At that stage, Thermodynamics (gas laws) falls out the equations and HYDRODYNAMICS (fluid laws) comes into play!!! Guns don't blow up from gas pressure!! THEY BLOW UP FROM HYDROSTATIC PRESSURE (LIQUID PRESSURE)!!! Think about the volume of water in a case being almost proportional to the weight of powder(density of the powder is slightly more than the density of water)! I've study the formulas from the military testing grounds and ballistics labs!!! And having 105 hrs of pure science (including calculus, DEF. EQ., and UPPER LEVEL Math for Physics), the formulas do show a high density plasma state of matter and energy!!!
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jelenko
Gold $$ Contributor
Plasma is one of four fundamental states of matter (the other three being solid, liquid, and gas) characterized by the presence of a significant portion of charged particles in any combination of ions or electrons. Plasma is not energy.
FWIW, thermodynamics is always present. It is about the transfer of heat.
Do you have a reference for that claim?
FWIW, thermodynamics is always present. It is about the transfer of heat.
Thermodynamics uses gas laws (Volume, Pressure, Heat)!! Just as I stated, powder is slightly more dense that water!! At a critical point in the burning of the powder, it acts as a fluid, not a gas!! The fluid absorbs the heat nullify thermodynamics!!! Hydrodynamics take over using hydrostatic pressure to punch the bullet through the lands! As the bullet is traveling down the barrel, the volume increase and the density decrease going back to a gas and given off the heat and thermodynamics come back into play!!! Plasma is a high energy state of matter!!! Plasma gives off light energy (photons or high energy electrons). Fire gives of photons (light)!! So does the burning of powder which you don't see accept at night!! The spectrum of that light can be determined by OPTICS (the study of light)!! And, conservation of matter hold true due to the photons being emitted when looks at the high energy state of matter called plasma!!! The remaining matter can become neutral or anion depending on the summation of charges of the byproducts of the reaction and how many photons were emitted!!
Smokeless powder fall into the explosive category!! The NO count, number of NO links or chains determines how explosive it is. The NO is an ion molecule (negatively charge). As the NO count increases per molecule, so does it explosive value(Decreasing burn time with increasing energy from larger molecular structure or mass density)! Double based powders have a small amounts of TNT which the gun cotton absorts making it stable!! TNT is the next step up with even more NO counts!! Add even more NOs, it's getting into the plastic explosives!!!
I would have to go back to the search engines to find the bunch of formulas for the internal ballistics formulas!! They will be in Calculus and Differential Equation forms and are photo copies of research papers from the 50s, 60s, and 70s!! Do you know how to read integrated and differential formulas (high level mathematics)??? You also need to be able you see the difference between thermo, hydro, and quantum formulas to understand the reports!! If you can, I will look for them!!! If you don't understand high level math, the papers will look like a foreign language to you!!!
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