Do you test to pass or test to fail?

[old_heli_logger]

Do you look for passing data and stop or do you continue to see if things fall apart? This applies to all aspects of handloading...
My latest testing has been looking for low ES... consistent low ES. Do you shoot 3 or 5 shots and plug that into your ballistic calculator and never test again or do you check your ES with every shot? I have found that consistent low ES is elusive (including different days, different temperatures, different humidities, moon phase, star alignment).
Anyone else seeing this in the real world?
Thanks!

 

[nwmnbowhunter]

It's either getting better or getting worse!!! I turn away from worse.

 

[CF Junkie]

I test for accuracy but I load for a seating depth, trim length and powder charge that will yield a velocity and Optimum Bullet Time (exit time) for a particular powder.
MV changes based upon variations in powder charge around 12 fps per 0.1 grain change, seating depth and trim length about 1 fps per 0.001 change.
Even my very best hand loads (all of them loaded with near identical seating depths and trim lengths (within 0.001) and powder charges (within 0.1 grains) have a SDs of 5 to 7 fps.
Those numbers are not generated from ladders, the velocities were expected to all be the same.
Factory rounds have SDs around 15 fps at best for supposedly the same loads for each round.
ES for those SDs could be about 3 to 4 times those numbers.

A lot of the variation in velocity is a product of the natural variation in primer and powder ignition.

The worst temperature sensitive powders make a difference of 1.24 fps per deg F. change.
The best temperature insensitive powders make a difference of less than 0.1 fps per deg F change.
How much temperature change do you think you experience between the first shot and the last shot in each of your muzzle velocity tests.

It is really tough to make any conclusions without an enormous amount of test data.

 

[STS]

I test to learn. I can learn from a positive result, or a negative result.

 

[JEFFPPC]

Only one test counts. Your target. I test to evaluate what I am doing. Target shows the only data that counts. My hobby is precision shooting not spreadsheets.

 

[222Jim]

Do you look for passing data and stop or do you continue to see if things fall apart? This applies to all aspects of handloading...
My latest testing has been looking for low ES... consistent low ES. Do you shoot 3 or 5 shots and plug that into your ballistic calculator and never test again or do you check your ES with every shot? I have found that consistent low ES is elusive (including different days, different temperatures, different humidities, moon phase, star alignment).
Anyone else seeing this in the real world?
Thanks!

It depends.....
(1) For load development, I test to learn through statistically valid samples. That means 4 5-shot groups (including chrono).

(2) To confirm my scope zero hasn't shifted due to getting bumped or banged around, 3 to 5 shots (but I use the 4 5-shot groups to set zero).

 

[Doom]

My latest testing has been looking for low ES... consistent low ES. Do you shoot 3 or 5 shots and plug that into your ballistic calculator and never test again or do you check your ES with every shot? I have found that consistent low ES is elusive (including different days, different temperatures, different humidities, moon phase, star alignment

ES is not a statistic. It is descriptive of two rounds out of any sample or population that is the result of extreme statistical standard deviation or to possible errors in the loading process (or any other proscess). For large sample sizes it will likely lie somewhere around 6x the standard deviation of the true standard deviation of the population. Note that that is about the extreme of the 99.7% of population.

ES at small sample sizes it is less and in general grows as the sample size increases. Just how would you define low ES or consisten ES. Standard deviation is a statistic. It describes the amount of variation in the individual samples in a test from the mean (average) of the samples. Because of random probabilities associated with sampling small sample sizes usually result in lower standard deviations than larger sample sizes. This is the natural result of 68% of the population lies with 1 standard deviation. That leaves 32% lying beyond 1 standard deviation. that means there is a more than 2 to 1 chance you pick a 1 standard deviation round each time you shoot or load a round. Unlike the mean or average value which tends to the normal distribution or Student's T distribution the Standard Deviation follows a Chi-Squared distribution which is heavily weighted to the low side for low sample numbers. For instance a test that yields a 9 fps standard deviation will have a 95% confidence interval between 5.39 and 25.86 fps. meaning that if a large number of test were run 95% of the SD's would fall between those numbers. 5% would be outside.

 

[old_heli_logger]

Wow! Great answers, thank you very much everyone!!!

 

[357Mag]

Do you look for passing data and stop or do you continue to see if things fall apart? This applies to all aspects of handloading...
My latest testing has been looking for low ES... consistent low ES. Do you shoot 3 or 5 shots and plug that into your ballistic calculator and never test again or do you check your ES with every shot? I have found that consistent low ES is elusive (including different days, different temperatures, different humidities, moon phase, star alignment).
Anyone else seeing this in the real world?
Thanks!

Oldhelllogger -

Howdy !

There are many reloaders/shooters today, that do load refinement w/o constant use of a chronograph and/or functions of a ( digital ) "ballistics calculator" like you mentioned.
These could be shooters like some varminters, hunters, and others that ( typically ) are not full tilt competition shooters.

When I'm doing load refinement range work, I myself establish what the max allowable charge is for a select powder, shot under a select bullet wt: and for use w/ a particular primer. * I stop increasing charge weight, before there is component or gun damage.
Keep load development safe, and not frenetic.

I thereafter reduce test power charges incrementally downward, until best accuracy is shown/proven. In varmint calibres, I have found the accuracy load' powder charge wt to be < 1 gr bellow the established max charge wt. Oft times, accuracy load' charge wt has ended up being found within just a few tenths of a grain of the max pressure load's charge wt. After reaching that point, I may make incidental slight reduction in charge wt, IF/when I take the gun to some incidental competition; and weather makes such adjustment necessary. But hey, that's just me.

I don't find my load development approach to be all that uniformed. After all, I have found a load that operates w/ safe pressures, and that provides best accuracy.
In that sense.... obtained muzzle velocity " is what it is ". After reaching THIS point, use of a chronograph and ( example ) on-line ballistics calculator comes into play; to allow generation of a bullet " drop chart " based on the chosen load's Mv. For me, a load's extreme spread and standard deviation are things I don't obsess on. Sometimes, it's sort of a " don't ask.... don't tell " type of deal; as regards ES and SD. The target shows you what works.

YRMV.


With regards,
357Mag

 

[Doom]

Oldhelllogger -

Howdy !

There are many reloaders/shooters today, that do load refinement w/o constant use of a chronograph and/or functions of a ( digital ) "ballistics calculator" like you mentioned.
These could be shooters like some varminters, hunters, and others that ( typically ) are not full tilt competition shooters.

When I'm doing load refinement range work, I myself establish what the max allowable charge is for a select powder, shot under a select bullet wt: and for use w/ a particular primer. * I stop increasing charge weight, before there is component or gun damage.
Keep load development safe, and not frenetic.

I thereafter reduce test power charges incrementally downward, until best accuracy is shown/proven. In varmint calibres, I have found the accuracy load' powder charge wt to be < 1 gr bellow the established max charge wt. Oft times, accuracy load' charge wt has ended up being found within just a few tenths of a grain of the max pressure load's charge wt. After reaching that point, I may make incidental slight reduction in charge wt, IF/when I take the gun to some incidental competition; and weather makes such adjustment necessary. But hey, that's just me.

I don't find my load development approach to be all that uniformed. After all, I have found a load that operates w/ safe pressures, and that provides best accuracy.
In that sense.... obtained muzzle velocity " is what it is ". After reaching THIS point, use of a chronograph and ( example ) on-line ballistics calculator comes into play; to allow generation of a bullet " drop chart " based on the chosen load's Mv. For me, a load's extreme spread and standard deviation are things I don't obsess on. Sometimes, it's sort of a " don't ask.... don't tell " type of deal; as regards ES and SD. The target shows you what works.

YRMV.


With regards,
357Mag

Great reply! What I didn't say in my epistle on ES and SD is exactly what you said. Find a load on target that works, be it at 100, 300, 600yds. If it works at short range and you are using good quality known components it's likely a good load. IF it opens up at distance then the chronograph will likely show you the issue in SD. But not with 3 or 5 rounds but 20 or 30 at least.

Two many people assume that the powder charge is the source of low round count SD variations for small changes. The truth is that it is likely attributable to all of the other variables that are changing shot to shot including Bullet, case primer, barrel condition, and minor powder weight variances.

 

[old_heli_logger]

Thanks again everyone! I guess my biggest ES question comes when I want to update my ballistic calculator...what velocity do I put in there? Worst case, best case, lowest, highest, average?

 

[mgunderson]

The wind gives me more problems. The apps don't account for the gaps in the tree lines and updrafts from the terrain. Average makes sense, but it depends on the consequences of being off one direction or the other.

 

[Mark611]

I try to shoot the most consistent loads from my rifles, I'm like CF, to many variables, IMO, you need good brass a good barrel the right powder and bullets and seating depth, and a good trigger and glass and tooling, everything must be the same when loading from case to case, JMO.

 

[charlie b]

I use a chronograph every time I go to the range and for almost every shot. 90% of the time I also document my target with each shot. Stored in the laptop for future reference.

Which number to use in the ballistic calculator? Depends. I've found that over time, eg, 50 rounds, that the fouling will cause a significant velocity increase, 20-50fps depending on cartridge. How hot the barrel gets is another factor.

So, if you are using the calculator for a cold bore shot you should use the velocity measured with a cold bore (and zero your rifle with a cold bore). If I am using the ballistic calculator at the range I just look at the avg of the last 5 rounds and input that vel in the app.

How do I find my 'best' load. I develop loads at 200 or 300yd. Target tells the tale. If two loads are similar but one has a better SD (5 round groups), I'll pick it as my preferred load.

 

[wywindsor]

I have read enough data and chased tails till for the last 2 years. What I have learned is this. Believe the target. There are some pretty good post here on subjects that tell the tell on what to do and what not to. I'm stubborn and still fight off idea's that float around in my small pea brain. But look up some post with Alex Wheeler load data. these are 6mm bra load data, 338 nmi load data. He refers alot to Tom that test the hell out of everything in and out of the box. Others chime in that are well known with test results or start new threads to avoid confrontation. Frank Green being one. Youtube guys like Keith Glasscock or Erick Cortina are great resources.

I have threads that make no sense to why. Look me up. Just another guy chasing what most already know. But what I do know is believe the target. I have test that are over 1.8 grains of powder at 500 that show powder to vertical results. Primer test to the most ridicules B.S. you can find. Now I follow the few greats that have posted here and youtubers that post proven methods that work. Not that something out of the box that nobody has ever seen could possibly come up but your the one to find it.

Just me but I think a electrically charged primer system would be best. Just for fun.

 

[Coyotefurharvester]

I thought the barrel either likes the bullet or not? That would be pass/fail.

 

[divingin]

Thanks again everyone! I guess my biggest ES question comes when I want to update my ballistic calculator...what velocity do I put in there? Worst case, best case, lowest, highest, average?

Since you want the data to representative of your overall shooting, I'd say average. That would minimize errors from shots that don't fall at the average value, no matter which way they're off.

 

[SGK]

Only one test counts. Your target. I test to evaluate what I am doing. Target shows the only data that counts. My hobby is precision shooting not spreadsheets.

That target is only good at that one distance. A nice little group at distance A will not carry through to distance B unless velocity spread is small.

 

[hoz53]

Thanks again everyone! I guess my biggest ES question comes when I want to update my ballistic calculator...what velocity do I put in there? Worst case, best case, lowest, highest, average?

when i want to do something like find elevation for a given distance with my solver i put in the average of the last three shots. i want to calulate for the actual velocity i am getting rite then

 

[hoz53]

I use a chronograph every time I go to the range and for almost every shot. 90% of the time I also document my target with each shot. Stored in the laptop for future reference.

Which number to use in the ballistic calculator? Depends. I've found that over time, eg, 50 rounds, that the fouling will cause a significant velocity increase, 20-50fps depending on cartridge. How hot the barrel gets is another factor.

So, if you are using the calculator for a cold bore shot you should use the velocity measured with a cold bore (and zero your rifle with a cold bore). If I am using the ballistic calculator at the range I just look at the avg of the last 5 rounds and input that vel in the app.

How do I find my 'best' load. I develop loads at 200 or 300yd. Target tells the tale. If two loads are similar but one has a better SD (5 round groups), I'll pick it as my preferred load.

“ fouling will cause a significant velocity increase”. thats interesting to me as my 6br does that often and the barrel is not even warm to the touch. I think that results in some ES that i cant reduce just by loading technique. there have been times i have shot much more accurately than i would have believed with the ES i had. why is this? i dont know
thanks