Okay so I know you should test a variety of charges between min and max to find the most accurate for your rifle, use the ladder test, etc. My question is why is that? Like, what does varying charges affect holding all other components constant other than velocity? Thanks. The cartridges in question are 308, 30-06, and ones similar.
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Re: Why isn't the most accurate load the max load?
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Engineer Chris Long's model of barrel behavior suggests (simply put, and in part) that the initial shock wave, generated by the powder charge's ignition, travels at the speed of sound in steel (about 18.000 fps) from the chamber to the muzzle, then back, in a repeated pattern. When this wave is present at the muzzle, there is naturally much turbulence and obturation of the "roundness" of the bore at the muzzle. However, when this main shock wave has reverberated back to the chamber end, the muzzle is relatively stable. This window of opportunity, according to Chris, is the best time for the bullet to exit the muzzle. The barrel is basically straight, and relatively calm.
</div></div>
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">The OCW load would then have the optimal amount of powder to push the bullet at just the right speed to be exiting the muzzle when this shock wave is at the other end (the chamber end) of the barrel.</div></div>
http://optimalchargeweight.embarqspace.com/
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Engineer Chris Long's model of barrel behavior suggests (simply put, and in part) that the initial shock wave, generated by the powder charge's ignition, travels at the speed of sound in steel (about 18.000 fps) from the chamber to the muzzle, then back, in a repeated pattern. When this wave is present at the muzzle, there is naturally much turbulence and obturation of the "roundness" of the bore at the muzzle. However, when this main shock wave has reverberated back to the chamber end, the muzzle is relatively stable. This window of opportunity, according to Chris, is the best time for the bullet to exit the muzzle. The barrel is basically straight, and relatively calm.
</div></div>
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">The OCW load would then have the optimal amount of powder to push the bullet at just the right speed to be exiting the muzzle when this shock wave is at the other end (the chamber end) of the barrel.</div></div>
http://optimalchargeweight.embarqspace.com/
Re: Why isn't the most accurate load the max load?
Ah thank you. That definitely helped a lot.
Ah thank you. That definitely helped a lot.
Re: Why isn't the most accurate load the max load?
As soon as I read the title of this thread I thought about all the things I've learned from glock24...
As soon as I read the title of this thread I thought about all the things I've learned from glock24...
Re: Why isn't the most accurate load the max load?
Usually a bedding issue when your hotter loads aren't the most accurate. Sometimes all it takes is a reassessment of the torque on the action screws. But sometimes it's just your luck.
Usually a bedding issue when your hotter loads aren't the most accurate. Sometimes all it takes is a reassessment of the torque on the action screws. But sometimes it's just your luck.
Re: Why isn't the most accurate load the max load?
I'll add another dimension to this:
I have foudn over the years that getting more velocity requires disproportionately more powder. In other words, to get "x" % more velocity, you need to add MORE than "x" % more powder. This makes sense, since the "energy" of the bullet (= 1/2 x mass x velocity x velocity) is proportional to the sqaure of the velocity, and it is the powder that supplies the energy.
More pwoder means bigger explosion and bigger effects from that explosion, inclduing probably more barrel vibration. This is, I suspect, why the most accurate rifles also have the heaviest barrels. The extra diameter and weight both work to better absorb the effects of a bigger explosion.
So, it probabyl shouldn't be surprising that the highest velocity load is very seldom the most accurate. Check the loading manualsfor confirmaiton (some do identify the most accurate loads found during the load testing). I don't think I've seen any situaitons where the strongest laod was also the most accurate.
And finally, yet another way to look at it: WHY WOULD the highest velocity load be the most accurate? I can't think of any reason it would be. In The World at large, maximized speed and best control rarely go together.
Jim G
I'll add another dimension to this:
I have foudn over the years that getting more velocity requires disproportionately more powder. In other words, to get "x" % more velocity, you need to add MORE than "x" % more powder. This makes sense, since the "energy" of the bullet (= 1/2 x mass x velocity x velocity) is proportional to the sqaure of the velocity, and it is the powder that supplies the energy.
More pwoder means bigger explosion and bigger effects from that explosion, inclduing probably more barrel vibration. This is, I suspect, why the most accurate rifles also have the heaviest barrels. The extra diameter and weight both work to better absorb the effects of a bigger explosion.
So, it probabyl shouldn't be surprising that the highest velocity load is very seldom the most accurate. Check the loading manualsfor confirmaiton (some do identify the most accurate loads found during the load testing). I don't think I've seen any situaitons where the strongest laod was also the most accurate.
And finally, yet another way to look at it: WHY WOULD the highest velocity load be the most accurate? I can't think of any reason it would be. In The World at large, maximized speed and best control rarely go together.
Jim G
Re: Why isn't the most accurate load the max load?
I believe Glock24 is referring to this paper...very interesting current thinking.
Optimal barrel time
Jim,
Your thoughts are based upon old and disproved thinking with regard to barrel harmonics.
The size of the explosion has nothing to do with accuracy.
If that were true our bench rest rifles would be using miniature cartridges and would be running very low pressure (they don't).
It would also mean 200 pound rifles shot better than 50 pound rifles (they don't shoot as well).
Further large magnums would work well with huge low pressure charges of overly slow powder or small charges of fast powder...All of this is proven not to work.
If you read the paper above you will find that the traditional thinking of barrel harmonics has been discounted.
Current thinking centers around a doughnut shaped pressure bulge traveling up the barrel. The OCW scatter node occurs as this bulge and the bullet coincide at the muzzle.
Heavier barrels are thought to restrict the size of this.
Then there is the matter of ignition.
As far as pressure and modern propellant goes if you do not reach approximately 45,000 psi there is no real accuracy. Reason for this is lower pressures cause a secondary pressure spike that hits the back of the bullet before it leaves the barrel.
Further reducing a charge will continue to increase secondary pressure to the point of detonation..Strange, but true. this is why we have minimum recommended powder charges.
I can see this on my pressure trace and then confirm on target.
As far as accuracy nodes and velocity goes many benchrest and F-class shooters run loads in the 55-65kpsi range. Some run higher if the rifle will shoot in that node.
Did you ever chrono you other loads?
I believe Glock24 is referring to this paper...very interesting current thinking.
Optimal barrel time
Jim,
Your thoughts are based upon old and disproved thinking with regard to barrel harmonics.
The size of the explosion has nothing to do with accuracy.
If that were true our bench rest rifles would be using miniature cartridges and would be running very low pressure (they don't).
It would also mean 200 pound rifles shot better than 50 pound rifles (they don't shoot as well).
Further large magnums would work well with huge low pressure charges of overly slow powder or small charges of fast powder...All of this is proven not to work.
If you read the paper above you will find that the traditional thinking of barrel harmonics has been discounted.
Current thinking centers around a doughnut shaped pressure bulge traveling up the barrel. The OCW scatter node occurs as this bulge and the bullet coincide at the muzzle.
Heavier barrels are thought to restrict the size of this.
Then there is the matter of ignition.
As far as pressure and modern propellant goes if you do not reach approximately 45,000 psi there is no real accuracy. Reason for this is lower pressures cause a secondary pressure spike that hits the back of the bullet before it leaves the barrel.
Further reducing a charge will continue to increase secondary pressure to the point of detonation..Strange, but true. this is why we have minimum recommended powder charges.
I can see this on my pressure trace and then confirm on target.
As far as accuracy nodes and velocity goes many benchrest and F-class shooters run loads in the 55-65kpsi range. Some run higher if the rifle will shoot in that node.
Did you ever chrono you other loads?
Re: Why isn't the most accurate load the max load?
X-fan: I'm afraid I would need to be better persuaded of that.
ONE example of why: Very few handgun loads attain 45,000 psi, and yet there are excellently accurate handguns. The lowly low pressure .22 in fact is very accurate in well made handguns.
Another example: My most accurate 338 Lapua load is nearer the minimum than the maximum, and although I have no pressure measuring equipment, the pressures at the minimum and maximum loads in that (Hodgdon) loading manual suggest that my load is very unlikely to be at or much above 45,000.
But, we need theories to examine.
For example, after using firearms for hundred of years, our firearms experts STILL cannot agree on what constitutes "stopping power"!
I'll read everything that comes to my attention, including the one you reference in your posting.
Jim G
X-fan: I'm afraid I would need to be better persuaded of that.
ONE example of why: Very few handgun loads attain 45,000 psi, and yet there are excellently accurate handguns. The lowly low pressure .22 in fact is very accurate in well made handguns.
Another example: My most accurate 338 Lapua load is nearer the minimum than the maximum, and although I have no pressure measuring equipment, the pressures at the minimum and maximum loads in that (Hodgdon) loading manual suggest that my load is very unlikely to be at or much above 45,000.
But, we need theories to examine.
For example, after using firearms for hundred of years, our firearms experts STILL cannot agree on what constitutes "stopping power"!
I'll read everything that comes to my attention, including the one you reference in your posting.
Jim G
Re: Why isn't the most accurate load the max load?
A couple or three random thoughts:
-Heavier barrels are perceived to be more accurate because they are easier for more people to make accurate....light barrels are a test of skill that not all people possess.
-Barrel harmonics are barrel harmonics are barrel harmonics....some understand it, some don't, some never will.
-Velocity is NOT the holy grail of all things bullet....all the time.
A couple or three random thoughts:
-Heavier barrels are perceived to be more accurate because they are easier for more people to make accurate....light barrels are a test of skill that not all people possess.
-Barrel harmonics are barrel harmonics are barrel harmonics....some understand it, some don't, some never will.
-Velocity is NOT the holy grail of all things bullet....all the time.
Re: Why isn't the most accurate load the max load?
Jim,
I would have to put pistol rounds and .22's into a different category that a precision cartridge. I don't pretend to understand the science of rimfires...It may be more complex than our center-fire stuff. Same for blackpowder.
Pistols and precision rifles are like apples and bananas...
Chronograph your other loads then tell me you are below 45kpsi...there is no way. Starting loads in most manuals are usually about 40,000 <span style="color: #990000">Copper Units</span> or 50,000 <span style="color: #990000">PSI</span>....Including Hodgdons..They do this to keep you safe.
Trip,
The more I shoot the more I agree about barrels shooting pretty much the same regardless of weight.
I have a light (8.25lbs) hunting 338Edge that is a real monster to hang onto and drive to its capabilities. Recently I set the rifle up (for accuracy testing only) adding a big (removable) brake, 2 oz jewel trigger, then bolted on a 8-32 Nightforce.
It shot near as well as its 18 pound twin!
Jim,
I would have to put pistol rounds and .22's into a different category that a precision cartridge. I don't pretend to understand the science of rimfires...It may be more complex than our center-fire stuff. Same for blackpowder.
Pistols and precision rifles are like apples and bananas...
Chronograph your other loads then tell me you are below 45kpsi...there is no way. Starting loads in most manuals are usually about 40,000 <span style="color: #990000">Copper Units</span> or 50,000 <span style="color: #990000">PSI</span>....Including Hodgdons..They do this to keep you safe.
Trip,
The more I shoot the more I agree about barrels shooting pretty much the same regardless of weight.
I have a light (8.25lbs) hunting 338Edge that is a real monster to hang onto and drive to its capabilities. Recently I set the rifle up (for accuracy testing only) adding a big (removable) brake, 2 oz jewel trigger, then bolted on a 8-32 Nightforce.
It shot near as well as its 18 pound twin!
Re: Why isn't the most accurate load the max load?
Also have to factor in a lot of times max loads = compression.
Then you have to figure that some loads will be compressed slightly unevenly, more grains on one side etc. The power can't "settle" as in a normal uncompressed load.
Also have to factor in a lot of times max loads = compression.
Then you have to figure that some loads will be compressed slightly unevenly, more grains on one side etc. The power can't "settle" as in a normal uncompressed load.
Re: Why isn't the most accurate load the max load?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: X-fan</div><div class="ubbcode-body">Jim,
Chronograph your other loads then tell me you are below 45kpsi...there is no way. Starting loads in most manuals are usually about 40,000 <span style="color: #990000">Copper Units</span> or 50,000 <span style="color: #990000">PSI</span>....Including Hodgdons..They do this to keep you safe.
</div></div>
You are correct that I forgot you were talking psi and the manuals often talk cup! Sorry.
Jim G
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: X-fan</div><div class="ubbcode-body">Jim,
Chronograph your other loads then tell me you are below 45kpsi...there is no way. Starting loads in most manuals are usually about 40,000 <span style="color: #990000">Copper Units</span> or 50,000 <span style="color: #990000">PSI</span>....Including Hodgdons..They do this to keep you safe.
</div></div>
You are correct that I forgot you were talking psi and the manuals often talk cup! Sorry.
Jim G
Re: Why isn't the most accurate load the max load?
Accuracy is about synchronizing the projectile's barrel transit time with the 'tuning fork' harmonic multiphase effects that each barrel inherently exhibits. This varies from barrel to barrel, even with supposedly 'identical ones'.
The maximum charge is about peak pressures, materials (chamber, cartridge case) expansion and elastic limits, and how these factors affect metal fatigue and long term safety. This varies from barrel to barrel, even with supposedly 'identical ones'.
The reasons even identical barrels will favor (slightly?) different load recipes has to do with manufacturing tolerance/variances. Things like toolmarks and process timings can result in variances in bore transit times when fired with 'identical' loads.
It typically requires individual load development in order to find 'ideal' load recipes for each barrel. The odds do not favor a coincidental correlation between best accuracy and the maximum safe load.
Maximum safe loads represent a computed/estimated peak load that resides within the pressure limits that good engineering practice demands. Accuracy nodes tend to be multiple load ranges that produce consistent POI's. While it may be possible to extrapolate accuracy nodes that extend beyond published maximum safe loads, and one may be able to get barrel to sustain the usage of such load recipes for an indefinite time, this piper must always be paid. The price is a paid in MTBF (an engineering terms that stands for Mean Time Between Failures) degradation.
Well designed firearms, employed with reasonable loads, will generally fail for reasons other than catastrophic pressure excursions (AKA Kabooms). MTBF degradation due to past-max load abuse means the Kaboom becomes the most likely point of failure.
Greg
Accuracy is about synchronizing the projectile's barrel transit time with the 'tuning fork' harmonic multiphase effects that each barrel inherently exhibits. This varies from barrel to barrel, even with supposedly 'identical ones'.
The maximum charge is about peak pressures, materials (chamber, cartridge case) expansion and elastic limits, and how these factors affect metal fatigue and long term safety. This varies from barrel to barrel, even with supposedly 'identical ones'.
The reasons even identical barrels will favor (slightly?) different load recipes has to do with manufacturing tolerance/variances. Things like toolmarks and process timings can result in variances in bore transit times when fired with 'identical' loads.
It typically requires individual load development in order to find 'ideal' load recipes for each barrel. The odds do not favor a coincidental correlation between best accuracy and the maximum safe load.
Maximum safe loads represent a computed/estimated peak load that resides within the pressure limits that good engineering practice demands. Accuracy nodes tend to be multiple load ranges that produce consistent POI's. While it may be possible to extrapolate accuracy nodes that extend beyond published maximum safe loads, and one may be able to get barrel to sustain the usage of such load recipes for an indefinite time, this piper must always be paid. The price is a paid in MTBF (an engineering terms that stands for Mean Time Between Failures) degradation.
Well designed firearms, employed with reasonable loads, will generally fail for reasons other than catastrophic pressure excursions (AKA Kabooms). MTBF degradation due to past-max load abuse means the Kaboom becomes the most likely point of failure.
Greg
Re: Why isn't the most accurate load the max load?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">
-Heavier barrels are perceived to be more accurate because they are easier for more people to make accurate....light barrels are a test of skill that not all people possess.
</div></div>
The math sez heavier barrels are more accurate because of stiffness, which reduces the amplitude of the harmonics. In theory, by choosing the right load, you can overcome this with a thin barrel... and rimfire benchrest shooters have proven this with pencil thin barrels and tuners.
In reality, thick barrels give you something else, which is a nice heat sink. If you are going to blow off 15 - 25 consecutive rounds in a match, you need to control this excessive heat some way. In a hunting gun, you likely are not going to shoot more than 2 - 3 consecutive rounds unless you are really really bad or really really greedy.
I don't know if talent has much to do with it. For hunting rifles, a thin contour barrel works. For matches, thicker is preferred. And it is not because competitive shooters are horrible shots.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">
-Heavier barrels are perceived to be more accurate because they are easier for more people to make accurate....light barrels are a test of skill that not all people possess.
</div></div>
The math sez heavier barrels are more accurate because of stiffness, which reduces the amplitude of the harmonics. In theory, by choosing the right load, you can overcome this with a thin barrel... and rimfire benchrest shooters have proven this with pencil thin barrels and tuners.
In reality, thick barrels give you something else, which is a nice heat sink. If you are going to blow off 15 - 25 consecutive rounds in a match, you need to control this excessive heat some way. In a hunting gun, you likely are not going to shoot more than 2 - 3 consecutive rounds unless you are really really bad or really really greedy.
I don't know if talent has much to do with it. For hunting rifles, a thin contour barrel works. For matches, thicker is preferred. And it is not because competitive shooters are horrible shots.
Re: Why isn't the most accurate load the max load?
I have gone to the range with ammo loaded in increments of 5 rounds of each powder weight.
Some loads look a lot more accurate than others.
But I have never been able to reproduce any of the results on the next trip to the range.
So I have given up on tuned loads, and just work up to the threshold of long brass life and then back off a safety margin.
What does it all mean?
I can't find the most accurate load, if it's advantages are down in the noise of my other problems of my crude testing.
I have gone to the range with ammo loaded in increments of 5 rounds of each powder weight.
Some loads look a lot more accurate than others.
But I have never been able to reproduce any of the results on the next trip to the range.
So I have given up on tuned loads, and just work up to the threshold of long brass life and then back off a safety margin.
What does it all mean?
I can't find the most accurate load, if it's advantages are down in the noise of my other problems of my crude testing.
Re: Why isn't the most accurate load the max load?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body">But I have never been able to reproduce any of the results on the next trip to the range.
So I have given up on tuned loads, and just work up to the threshold of long brass life and then back off a safety margin.
What does it all mean?
I can't find the most accurate load, if it's advantages are down in the noise of my other problems of my crude testing. </div></div>
Your anlysis of WHY you are not getting repeatable results is accurate. We all struggle with that sometimes, if (a) we are simply not good enough shooters to shoot consistently enough, or (b) we have one or more uncontrolled variables in the way we are making the ammo.
But, when I have begun shooting a rilfe new to me, I have never hesitated to invite someone who I KNOW is a good and consistent shooter to fire a few groups for me using my rifle and ammo. He always thinks it's great because he gets free ammo and time behind a rifle he does not need to buy to try, and I get a more realistic test of my ammo.
Jim G
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body">But I have never been able to reproduce any of the results on the next trip to the range.
So I have given up on tuned loads, and just work up to the threshold of long brass life and then back off a safety margin.
What does it all mean?
I can't find the most accurate load, if it's advantages are down in the noise of my other problems of my crude testing. </div></div>
Your anlysis of WHY you are not getting repeatable results is accurate. We all struggle with that sometimes, if (a) we are simply not good enough shooters to shoot consistently enough, or (b) we have one or more uncontrolled variables in the way we are making the ammo.
But, when I have begun shooting a rilfe new to me, I have never hesitated to invite someone who I KNOW is a good and consistent shooter to fire a few groups for me using my rifle and ammo. He always thinks it's great because he gets free ammo and time behind a rifle he does not need to buy to try, and I get a more realistic test of my ammo.
Jim G
Re: Why isn't the most accurate load the max load?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body">I have gone to the range with ammo loaded in increments of 5 rounds of each powder weight.
Some loads look a lot more accurate than others.
But I have never been able to reproduce any of the results on the next trip to the range.
So I have given up on tuned loads, and just work up to the threshold of long brass life and then back off a safety margin.
What does it all mean?
I can't find the most accurate load, if it's advantages are down in the noise of my other problems of my crude testing. </div></div>
Load development is all about method.
5 random loads is just like wishing for good groups...You may hit it right or you may not.
The best place to start is developing an Optimum Charge Weight or OCW.
Go here and Read
What you are looking for is a string of powder weights that shoot to the same point of impact at 100 yards. This gives you a base load that is forgiving of lots of little sins.
If you cant find an OCW you may have a rifle problem or be using the wrong powder.
Sometimes powders a click too slow are completely unresponsive...An OCW test will reveal all.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Clark</div><div class="ubbcode-body">I have gone to the range with ammo loaded in increments of 5 rounds of each powder weight.
Some loads look a lot more accurate than others.
But I have never been able to reproduce any of the results on the next trip to the range.
So I have given up on tuned loads, and just work up to the threshold of long brass life and then back off a safety margin.
What does it all mean?
I can't find the most accurate load, if it's advantages are down in the noise of my other problems of my crude testing. </div></div>
Load development is all about method.
5 random loads is just like wishing for good groups...You may hit it right or you may not.
The best place to start is developing an Optimum Charge Weight or OCW.
Go here and Read
What you are looking for is a string of powder weights that shoot to the same point of impact at 100 yards. This gives you a base load that is forgiving of lots of little sins.
If you cant find an OCW you may have a rifle problem or be using the wrong powder.
Sometimes powders a click too slow are completely unresponsive...An OCW test will reveal all.
Re: Why isn't the most accurate load the max load?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Carter Mayfield</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">
-Heavier barrels are perceived to be more accurate because they are easier for more people to make accurate....light barrels are a test of skill that not all people possess.
</div></div>
The math sez heavier barrels are more accurate because of stiffness, which reduces the amplitude of the harmonics. In theory, by choosing the right load, you can overcome this with a thin barrel... and rimfire benchrest shooters have proven this with pencil thin barrels and tuners.
In reality, thick barrels give you something else, which is a nice heat sink. If you are going to blow off 15 - 25 consecutive rounds in a match, you need to control this excessive heat some way. In a hunting gun, you likely are not going to shoot more than 2 - 3 consecutive rounds unless you are really really bad or really really greedy.
I don't know if talent has much to do with it. For hunting rifles, a thin contour barrel works. For matches, thicker is preferred. And it is not because competitive shooters are horrible shots. </div></div>
I rest my case..........
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Carter Mayfield</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">
-Heavier barrels are perceived to be more accurate because they are easier for more people to make accurate....light barrels are a test of skill that not all people possess.
</div></div>
The math sez heavier barrels are more accurate because of stiffness, which reduces the amplitude of the harmonics. In theory, by choosing the right load, you can overcome this with a thin barrel... and rimfire benchrest shooters have proven this with pencil thin barrels and tuners.
In reality, thick barrels give you something else, which is a nice heat sink. If you are going to blow off 15 - 25 consecutive rounds in a match, you need to control this excessive heat some way. In a hunting gun, you likely are not going to shoot more than 2 - 3 consecutive rounds unless you are really really bad or really really greedy.
I don't know if talent has much to do with it. For hunting rifles, a thin contour barrel works. For matches, thicker is preferred. And it is not because competitive shooters are horrible shots. </div></div>
I rest my case..........
Re: Why isn't the most accurate load the max load?
I'm in the camp that asserts the harmonics are the strongest influencing factor. Catch the right node as the bullet exits the barrel and you have a winner. Do it the same way time after time and you have a bunch of winners.
I'm in the camp that asserts the harmonics are the strongest influencing factor. Catch the right node as the bullet exits the barrel and you have a winner. Do it the same way time after time and you have a bunch of winners.
Re: Why isn't the most accurate load the max load?
I think there are MULTIPLE factors, and one problem is that (a) we individually don't know all the factors at work, and (b) we have a hard enough time controlling the ones we know about.
But, that is what makes reloading so interesting to do . . .
Jim G
I think there are MULTIPLE factors, and one problem is that (a) we individually don't know all the factors at work, and (b) we have a hard enough time controlling the ones we know about.
But, that is what makes reloading so interesting to do . . .
Jim G
Re: Why isn't the most accurate load the max load?
Harmonics are not at all hard to understand, nor deal with.....but just like everything else, it's not for everyone to grasp, and there will always be those who believe it's nothing short of black magic.
Harmonics are not at all hard to understand, nor deal with.....but just like everything else, it's not for everyone to grasp, and there will always be those who believe it's nothing short of black magic.
Re: Why isn't the most accurate load the max load?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JimGnitecki</div><div class="ubbcode-body">I'll add another dimension to this:
I have foudn over the years that getting more velocity requires disproportionately more powder. In other words, to get "x" % more velocity, you need to add MORE than "x" % more powder. This makes sense, since the "energy" of the bullet (= 1/2 x mass x velocity x velocity) is proportional to the sqaure of the velocity, and it is the powder that supplies the energy.
More pwoder means bigger explosion and bigger effects from that explosion, inclduing probably more barrel vibration. This is, I suspect, why the most accurate rifles also have the heaviest barrels. The extra diameter and weight both work to better absorb the effects of a bigger explosion.
So, it probabyl shouldn't be surprising that the highest velocity load is very seldom the most accurate. Check the loading manualsfor confirmaiton (some do identify the most accurate loads found during the load testing). I don't think I've seen any situaitons where the strongest laod was also the most accurate.
And finally, yet another way to look at it: WHY WOULD the highest velocity load be the most accurate? I can't think of any reason it would be. In The World at large, maximized speed and best control rarely go together.
Jim G </div></div>
Jim look at the Nosler #6 book it has a lot of loads that are most accurate at max load
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JimGnitecki</div><div class="ubbcode-body">I'll add another dimension to this:
I have foudn over the years that getting more velocity requires disproportionately more powder. In other words, to get "x" % more velocity, you need to add MORE than "x" % more powder. This makes sense, since the "energy" of the bullet (= 1/2 x mass x velocity x velocity) is proportional to the sqaure of the velocity, and it is the powder that supplies the energy.
More pwoder means bigger explosion and bigger effects from that explosion, inclduing probably more barrel vibration. This is, I suspect, why the most accurate rifles also have the heaviest barrels. The extra diameter and weight both work to better absorb the effects of a bigger explosion.
So, it probabyl shouldn't be surprising that the highest velocity load is very seldom the most accurate. Check the loading manualsfor confirmaiton (some do identify the most accurate loads found during the load testing). I don't think I've seen any situaitons where the strongest laod was also the most accurate.
And finally, yet another way to look at it: WHY WOULD the highest velocity load be the most accurate? I can't think of any reason it would be. In The World at large, maximized speed and best control rarely go together.
Jim G </div></div>
Jim look at the Nosler #6 book it has a lot of loads that are most accurate at max load
Re: Why isn't the most accurate load the max load?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: OKIE2</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JimGnitecki</div><div class="ubbcode-body">I'll add another dimension to this:
I have foudn over the years that getting more velocity requires disproportionately more powder. In other words, to get "x" % more velocity, you need to add MORE than "x" % more powder. This makes sense, since the "energy" of the bullet (= 1/2 x mass x velocity x velocity) is proportional to the sqaure of the velocity, and it is the powder that supplies the energy.
More pwoder means bigger explosion and bigger effects from that explosion, inclduing probably more barrel vibration. This is, I suspect, why the most accurate rifles also have the heaviest barrels. The extra diameter and weight both work to better absorb the effects of a bigger explosion.
So, it probabyl shouldn't be surprising that the highest velocity load is very seldom the most accurate. Check the loading manualsfor confirmaiton (some do identify the most accurate loads found during the load testing). I don't think I've seen any situaitons where the strongest laod was also the most accurate.
And finally, yet another way to look at it: WHY WOULD the highest velocity load be the most accurate? I can't think of any reason it would be. In The World at large, maximized speed and best control rarely go together.
Jim G </div></div>
Jim look at the Nosler #6 book it has a lot of loads that are most accurate at max load </div></div>
That is interesting. I will try to sneak a peek at a Nosler manual (I hate to buy something I don't normally use, as there is no extra room in an RV for surplus stuff).
Note that some manuals have been becoming extremely conservative. They simply stop at a really low powder load. Sierra is a prime example. Comapring their loads to that of Hodgdon shows an enormous difference in maximum load.
Jim G
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: OKIE2</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JimGnitecki</div><div class="ubbcode-body">I'll add another dimension to this:
I have foudn over the years that getting more velocity requires disproportionately more powder. In other words, to get "x" % more velocity, you need to add MORE than "x" % more powder. This makes sense, since the "energy" of the bullet (= 1/2 x mass x velocity x velocity) is proportional to the sqaure of the velocity, and it is the powder that supplies the energy.
More pwoder means bigger explosion and bigger effects from that explosion, inclduing probably more barrel vibration. This is, I suspect, why the most accurate rifles also have the heaviest barrels. The extra diameter and weight both work to better absorb the effects of a bigger explosion.
So, it probabyl shouldn't be surprising that the highest velocity load is very seldom the most accurate. Check the loading manualsfor confirmaiton (some do identify the most accurate loads found during the load testing). I don't think I've seen any situaitons where the strongest laod was also the most accurate.
And finally, yet another way to look at it: WHY WOULD the highest velocity load be the most accurate? I can't think of any reason it would be. In The World at large, maximized speed and best control rarely go together.
Jim G </div></div>
Jim look at the Nosler #6 book it has a lot of loads that are most accurate at max load </div></div>
That is interesting. I will try to sneak a peek at a Nosler manual (I hate to buy something I don't normally use, as there is no extra room in an RV for surplus stuff).
Note that some manuals have been becoming extremely conservative. They simply stop at a really low powder load. Sierra is a prime example. Comapring their loads to that of Hodgdon shows an enormous difference in maximum load.
Jim G
Re: Why isn't the most accurate load the max load?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JimGnitecki</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: OKIE2</div><div class="ubbcode-body">
Jim look at the Nosler #6 book it has a lot of loads that are most accurate at max load </div></div>
That is interesting. I will try to sneak a peek at a Nosler manual (I hate to buy something I don't normally use, as there is no extra room in an RV for surplus stuff).
Note that some manuals have been becoming extremely conservative. They simply stop at a really low powder load. Sierra is a prime example. Comapring their loads to that of Hodgdon shows an enormous difference in maximum load.
Jim G </div></div>
Pick powders with optimal burn rates (powders that give the most velocity) you can most often expect best accuracy at the maximum load or within 2 grains down from max (55ish-60,000psi).
I have fifth edition Nosler reloading manual and it is not conservative. In fact there are loads in there that will get you into trouble.
They don't have the 338 lapua in this one, but they do have the 338RUM and I confirm the following data.
225 grain bullets:
91gr RL-22 for 3160fps max load.
96gr RL-25 for 3177fps 2 grains below max. (this is max in my rifle and there is no way I would take it to 98gr).
93gr IMR-7828 for 3147fps max load
H-1000 (too slow at this weight) and IMR 4350 (too fast with the 225gr) show best accuracy at the lowest load listed.... Nosler does not list H-1000 with the 250gr + bullet weights, but I know H-1000 shoots alongside the rest with heavy bullet weights at 60kpsi.
Lowering bullet weight to 180grain brings IMR_4350 into optimal burn rate and Nosler shows it most accurate wide open.
No experience with this one, but I believe Nosler.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JimGnitecki</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: OKIE2</div><div class="ubbcode-body">
Jim look at the Nosler #6 book it has a lot of loads that are most accurate at max load </div></div>
That is interesting. I will try to sneak a peek at a Nosler manual (I hate to buy something I don't normally use, as there is no extra room in an RV for surplus stuff).
Note that some manuals have been becoming extremely conservative. They simply stop at a really low powder load. Sierra is a prime example. Comapring their loads to that of Hodgdon shows an enormous difference in maximum load.
Jim G </div></div>
Pick powders with optimal burn rates (powders that give the most velocity) you can most often expect best accuracy at the maximum load or within 2 grains down from max (55ish-60,000psi).
I have fifth edition Nosler reloading manual and it is not conservative. In fact there are loads in there that will get you into trouble.
They don't have the 338 lapua in this one, but they do have the 338RUM and I confirm the following data.
225 grain bullets:
91gr RL-22 for 3160fps max load.
96gr RL-25 for 3177fps 2 grains below max. (this is max in my rifle and there is no way I would take it to 98gr).
93gr IMR-7828 for 3147fps max load
H-1000 (too slow at this weight) and IMR 4350 (too fast with the 225gr) show best accuracy at the lowest load listed.... Nosler does not list H-1000 with the 250gr + bullet weights, but I know H-1000 shoots alongside the rest with heavy bullet weights at 60kpsi.
Lowering bullet weight to 180grain brings IMR_4350 into optimal burn rate and Nosler shows it most accurate wide open.
No experience with this one, but I believe Nosler.
