Experiment for quantifying lot to lot variations of powders

[Michael Courtney]

What purpose or benefit rises in challenging a claim of a single powder provider?
If the results 'seem' favorable to one, then what of the others?
If the results sway otherwise, who would benefit or suffer given any libelous utterance of it?

So it would be wrong to test the accuracy claims of only one rifle manufacturer?

It would be wrong to test the BC claims of only one new line of bullets?

It would be wrong to test the friction reducing claims of only one lubricant?

It would be wrong to measure the MPG of only one make of hybrid auto?

To my knowledge, only the Extreme line of rifle powders makes claims regarding lot to lot consistency.

Similarly, to my knowledge, only one major bullet maker makes claims regarding the weight consistency of its bullets. Was it wrong to focus our paper comparing the actual measurements on bullets from that manufacturer?

See:

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA555976

Is there some kind of "fairness" rule that when testing a marketing claim, one needs to include multiple brands? What if the other brands do not make any claims?

To my knowledge, Hodgdon Extreme powders are the only powders specifically chosen for US Sniper applications, and are usually the first powders looked at for long range law enforcement and military applications. These people care more about whether Hodgdon powders live up to the marketing claims than about the powders that make no such claims.

 

[Mikecr]

All experimenting is fine & good, and as long as the investigation is yours, for only you, then of course you can run it as you like. I do this a lot.
On the other hand, if you intend to slip any results into a gun rag for pseudo 'peer review', it won't go over well. It won't fly in forums either.

Just sayin

 

[Topshot]

This is the set up you need to do your test.
25m indoor range, controlled environment, universal receiver, industrial ballistic chronographs, computer based logging equipment.

 

[Michael Courtney]

This is the set up you need to do your test.
25m indoor range, controlled environment, universal receiver, industrial ballistic chronographs, computer based logging equipment.

I've found it much easier to load for low velocity variations in most of the shoulder fired rifles I've loaded for than for the barrels in universal receivers. This runs counter to my intuition. But my experience is that good case prep, careful powder selection and measurement, selecting a quality bullet, and a good barrel cleaning routine are all that is needed for load consistency in most of my shoulder fired rifles. Universal receivers and rifles held in a ransom rest are a different deal. I would have though adding effective mass and/or tightly coupling the rifle to a shooting bench would be an advantage to consistency. I think perhaps there is a reason why the reloading manuals do not report standard deviations or extreme spreads along with their velocities.

 

[Bart B]

We are ballistics professionals. We have strain based systems, including the PressureTraceII. We also have PZT-based pressure measurement systems.

Do you also have universal receivers solid mounted for muzzle velocity tests to eliminate the rifle holding variables that prevent accurate muzzle velocties from being observed?

And are SAAMI spec'd test barrels mounted in those receivers?

Will you use the "SAAMI twist" on cartridges before loading them in the chamber?

 

[Topshot]

I've found it much easier to load for low velocity variations in most of the shoulder fired rifles I've loaded for than for the barrels in universal receivers. This runs counter to my intuition. But my experience is that good case prep, careful powder selection and measurement, selecting a quality bullet, and a good barrel cleaning routine are all that is needed for load consistency in most of my shoulder fired rifles. Universal receivers and rifles held in a ransom rest are a different deal. I would have though adding effective mass and/or tightly coupling the rifle to a shooting bench would be an advantage to consistency. I think perhaps there is a reason why the reloading manuals do not report standard deviations or extreme spreads along with their velocities.

It may seem counter intuitive and there is a reason for this. The shoulder acts as a shock absorber and evens out the differences between loads. This is due to small differences in recoil from shot to shot. With a solid universal receiver mounted in a solid stand, the variations between loads is not masked by a shock absorbing medium and stand out as differences in velocity. Basic physics, for every actions there is an equal and opposite reaction. Throw is a shock absorbing device in the middle and the reactions are more consistent in value.
Just my take on things.

 

[FEENIX]

GEEZ! Variety is the spice of life.

It's your time and dime, ... do your experiment. You do not need anybody's permission ... test away!

 

[Bart B]

I've found it much easier to load for low velocity variations in most of the shoulder fired rifles I've loaded for than for the barrels in universal receivers. This runs counter to my intuition. But my experience is that good case prep, careful powder selection and measurement, selecting a quality bullet, and a good barrel cleaning routine are all that is needed for load consistency in most of my shoulder fired rifles. Universal receivers and rifles held in a ransom rest are a different deal. I would have though adding effective mass and/or tightly coupling the rifle to a shooting bench would be an advantage to consistency. I think perhaps there is a reason why the reloading manuals do not report standard deviations or extreme spreads along with their velocities.

Looks to me like you don't mind if there's errors in your velocity data. And inaccurate data's OK by you.

The vast majority of published data (spoken, printed or internet based) on velocity, accuracy and so many other things regarding the shooting sports includes all the human caused variables. No wonder there's dozens (hundreds?) of favorite load recipies. Especially those derived from shoulder fired rifles resting atop something on a bench. I"ve personally witnessed a 60 fps spread in the same rifle-ammo combination between me and a friend shooting the same rifle shoulder fired from a bench. Others have reported up to 100 fps. And nobody holds a rifle to shoot test groups for accuracy as repeatable as a machine rest (accuracy cradle) does. Totally free recoiling benchrest rifles are a very close second.

Velocity data is only 100% valid from fixed barrels. Anytime the barrel moves backwards as the bullet moves down the barrel, muzzle velocity will be less than if that barrel was fixed. Shame on you, Newton, for coming up with your third law of motion that so many people fail to obey.

 

[coues7]

Should be interesting

 

[rscott5028]

Michael,

I didn't mean to sound negative or onerous. To the contrary, I believe you're up to the task with proper funding.

In one of your responses, you indicated you wanted to test Hodgdon's claim.

So, why not tell Hodgdon what you're up to and ask them to provide their methodology?

Any scientifically valid experiment should be repeatable. You can report on whether you get the same results and the benefits or limitations of such a test.

And if they don't want to reveal their methods, tell them you'll report on that and conduct your own experiment.

If their method requires a $100k, then it'd be an uphill battle to debunk it on a shoestring budget.

-- richard

 

[Michael Courtney]

Michael,

I didn't mean to sound negative or onerous. To the contrary, I believe you're up to the task with proper funding.

In one of your responses, you indicated you wanted to test Hodgdon's claim.

So, why not tell Hodgdon what you're up to and ask them to provide their methodology?

Any scientifically valid experiment should be repeatable. You can report on whether you get the same results and the benefits or limitations of such a test.

And if they don't want to reveal their methods, tell them you'll report on that and conduct your own experiment.

If their method requires a $100k, then it'd be an uphill battle to debunk it on a shoestring budget.

-- richard

Good idea. I like it. However, our past experience is that once we start down that road, there are often expectations of confidentiality and non-disclosure, so I may not be able to report on everything I learn.

 

[rscott5028]

No doubt Hodgdon's claims are sufficiently vague as to give them safe harbour if challenged.

The whole NDA thing is somewhat self-defeating. But, perhaps they'd like to comment on the structure of your experiement before you execute?

Often times an experiement of the scope you're talking about is a great tickler just to get people thinking about the magnitude and significance of such claims.

Alternatively, you might want to have a look at VhitaVuori or another good powder that doesn't outright make such claims.

Kevin Thomas would have a worthwhile opinion.

-- richard

 

[Michael Courtney]

No doubt Hodgdon's claims are sufficiently vague as to give them safe harbour if challenged.

This could be the case. But it may also be that then independent parties begin carefully measuring things, the manufacturer's and distributors become more careful about their measurements and the claims they make.

Consider ballistic coefficient, for example. Between 2000 and 2010, several independent parties, including us, began earnestly reporting the results of careful BC measurements. About the same time, several companies (including Barnes and Berger) began careful measuring and revising the published BCs of almost all of their bullets. I also think Berger has improved considerably on their lot to lot consistency. They also hired Bryan Litz to help measure BCs and assist in the design of new bullets with higher BCs.

Other companies such as Hornady seemed to become more careful in measuring and reporting accurate BC numbers for their new lines of bullets, without revising their published BCs for older lines of bullets. Some other companies (such as Nosler) seemed to continue to publish more "theoretical" numbers which tend to find larger disagreement with BCs determined by independent parties. Still other companies (Sierra) were found to be publishing BC numbers in pretty good agreement with those determined by independent parties.

So my bottom line is that many suppliers have a positive history of improving their products and specifications as a result of independent product testing.

 

[Bart B]

So my bottom line is that many suppliers have a positive history of improving their products and specifications as a result of independent product testing.

I believe Sierra, Barnes and Berger are the only bullet makers determining BC by conducting their own time of flight tests. The others probably use Greenhill or other inaccurate formulas based on bullet weight and dimensions.

And Sierra may be the only one that publishes/lists two or more BC's for different velocity bands which typically gives the most accurate trajectory data. Berger admits they average the BC's they get in different velocity bands for each bullet, but that's close enough for 99% of folks applications.

Bullet companies also use different methods and practices for measuring their bullets' accuracy. Sierra may be the only one that full length sizes their cases.