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Statistical Ghosts and Seeing Patterns


Popsbengo

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I've been reading  a lot of posts and articles on various load development techniques and I am beginning to think there's an awful lot of statistical "technique" applied without a statistical understanding of "noise".  Various tests like OCW and Ladder tests, Plateaux tests and Satterlee (spelling) - all these techniques seem to rely on high precision and control of reloading practice but draw conclusions from very small data sets. Much of the testing is in an uncontrolled environment (the range), not to mention the standards of equipment being used to measure weight and other dimensional factors and variabilities such as temperature changes during testing, wind etc etc.  It seems to me that data patterns will appear due to statistical noise but are interpreted as meaningful data.  If we toss a fair coin we will ultimately get 50:50 heads and tails - but not if we toss it ten times and draw a conclusion as to the next set of data being the same.

Some of the claims by well known shooting "expert" forums (usually American) seem to make outrageous claims for their particular or preferred method unsupported by repeated experiments.

Obviously certain loads work better and I do believe that barrel harmonics, bullet seating OAL are well established and demonstrated effects however I'm unconvinced by much of the other chatter.  Am I wrong and have the top performing shooters converged on a load dev. technique that gives predictable and repeatable results?

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Nothing is that certain as there all varibles. Power varies lot to lot. Bullets vary, primers vary, cases vary, conditions vary just to name a few. We tend to try these things and stick with what works for ourselves.

My approach is going with what groups the best and fine tune if it needs it. Check velocity after

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Ok here's  my take on it if you have a load that really works i.e. 308 out to 1000yards and you reached that load by ocw why not cross check a new  technique by trying that technique and seeing if you arrive at the same load that's what I did.

 I looked for the flat spot in the  velocity curve and found I was on the same load powder wise  as my established load already had.

 

 

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I agree. People seem to want to find their perfect load in as little rounds as possible and tend to make some hasty decisions as to what works and what doesn't. My circumstances are different than most UK shooters in that I have an unlimited resource for powder and bullets, so when i load, I pick a powder that gives me the velocity range I want/need with the lowest pressures. I then choose a starting load and load fifty. I shoot them. I don't bother chronographing unless the load shows signs of being promising. In the mean while I wring the load out at various distances and get in some meaningful trigger time.  If I continue with that component combination I may up the charge what I deem appropriate and repeat. You would be surprised at how many deer I've killed or steel plates I've tattooed with loads that were not fully "developed' at the time. One of my better 130 grain 6.5 CM loads was shot by a friend when he forgot his ammo at a long range gathering. I gave hin the 50 rounds i'd loaded to test. He beat up the plates out to 1000 yards and I kept track of his elevation changes. After observing 50 rounds perform at ranges from 550 to 1004 yards I concluded the load was good enough as it was. I could not have deduced that from a four shot group....~Andrew

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16 hours ago, Andrew said:

I agree. People seem to want to find their perfect load in as little rounds as possible and tend to make some hasty decisions as to what works and what doesn't. My circumstances are different than most UK shooters in that I have an unlimited resource for powder and bullets.....

You lucky chap! Do you need an understudy?  I don't eat much and I'll help you out shooting all that ammo 😂🤣

I have similar experiences with "less than optimal" loads doing well,  I think the pursuit of that perfect load should take second place to the pleasure of shooting !

 

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3 hours ago, Popsbengo said:

I have similar experiences with "less than optimal" loads doing well,  I think the pursuit of that perfect load should take second place to the pleasure of shooting !

 

Couldn’t agree more pops! My 6.5 CM load was pretty much stumbled upon but consistently shoots 0.5 - 0.75 moa at all ranges I’ve tried it at thus far. Delighted with it today at Kingsbury 600 in some choppy wind.

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3 minutes ago, SMLE said:

Couldn’t agree more pops! My 6.5 CM load was pretty much stumbled upon but consistently shoots 0.5 - 0.75 moa at all ranges I’ve tried it at thus far. Delighted with it today at Kingsbury 600 in some choppy wind.

Funny, you look older in your picture than in real life?  I didn't notice any wind effects with 300gn bombs at 2950ft/sec 😁😁  Just bad lads moving the marker about😄

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7 hours ago, Popsbengo said:

You lucky chap! Do you need an understudy?  I don't eat much and I'll help you out shooting all that ammo 😂🤣

I have similar experiences with "less than optimal" loads doing well,  I think the pursuit of that perfect load should take second place to the pleasure of shooting !

 

Absolutely. Pick a load and shoot. Trigger time is good time.

No need for an understudy, thanks. I have a girl friend who thinks nothing of running through Federal Match Primers like they were free. The first time i put her behind my Tikka CTR 6.5 she gleefully shot all my ammo at the 650 to 810 yard targets. When she had nothing but a pile of empty brass she looked up with an expectant look on her face as if i was going to pull another 100 rounds out of my back pocket. Youth! I make her reload her own now....~Andrew

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On 3/23/2019 at 6:46 PM, Popsbengo said:

I've been reading  a lot of posts and articles on various load development techniques and I am beginning to think there's an awful lot of statistical "technique" applied without a statistical understanding of "noise".  Various tests like OCW and Ladder tests, Plateaux tests and Satterlee (spelling) - all these techniques seem to rely on high precision and control of reloading practice but draw conclusions from very small data sets. Much of the testing is in an uncontrolled environment (the range), not to mention the standards of equipment being used to measure weight and other dimensional factors and variabilities such as temperature changes during testing, wind etc etc.  It seems to me that data patterns will appear due to statistical noise but are interpreted as meaningful data.  If we toss a fair coin we will ultimately get 50:50 heads and tails - but not if we toss it ten times and draw a conclusion as to the next set of data being the same.

Some of the claims by well known shooting "expert" forums (usually American) seem to make outrageous claims for their particular or preferred method unsupported by repeated experiments.

Obviously certain loads work better and I do believe that barrel harmonics, bullet seating OAL are well established and demonstrated effects however I'm unconvinced by much of the other chatter.  Am I wrong and have the top performing shooters converged on a load dev. technique that gives predictable and repeatable results?

I think this appears in a number of areas in life. The systems are highly suspect, but in the absence of a system that is demonstrably valid we have to do "something".  It may (or may not) be crap but its the best we can imagine...

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I've never seen it done with centrefire, but the small-bore range I use have a clamp that bolts to the concrete floor and supports the rifle rigidly. It's used for grading ammunition and generally seeing how good/bad a rifle is.

This would eliminate "operator error" when trying new centrefire loads. It certainly told me which 22LR to feed my match 54.

Pete

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28 minutes ago, Re-Pete said:

I've never seen it done with centrefire, but the small-bore range I use have a clamp that bolts to the concrete floor and supports the rifle rigidly. It's used for grading ammunition and generally seeing how good/bad a rifle is.

This would eliminate "operator error" when trying new centrefire loads. It certainly told me which 22LR to feed my match 54.

Pete

That would certainly account for operator error however my specific critique is the statistical errors related to reloading practices and measurement of muzzle velocity.  Random fluctuations created by tolerances of approximately 1/2 % to 1%  in measuring weight and velocity would easily wipe out the observed "flat spots" I've seen presented on charts; and that's without primer tolerances too.  For sure shooting dozens of rounds at targets and collating the grouping results is by far the best I can see.

Only slightly off topic, with regard to .22LR,  I still find it quite surprising as to how certain ammo works really well and other ammo is pants - even given very similar velocities and all being the same bullet weight.  My CZ455 loves RWS Match but not Eley Match:  my bench-rest scores drop at least 5%. Eley Club, CCI etc and it's 10% off.

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This is all very interesting. I've had seemingly excellent 100yd loads perform terribly at ranges beyond 500yds. Chronographing those same loads at a later date told me why.

So who can explain manufactures match ammunition often performing well in multiple rifles? How do they arrive at the sweet spot? 

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1 hour ago, MJR said:

This is all very interesting. I've had seemingly excellent 100yd loads perform terribly at ranges beyond 500yds. Chronographing those same loads at a later date told me why.

So who can explain manufactures match ammunition often performing well in multiple rifles? How do they arrive at the sweet spot? 

Testing thousands I suspect.

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Eley Match........the girls ancient Supermatch (square bolt head, single extractor) likes SK Standard.

Pete

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A seriously competitive shooter once told me that consistent neck tension was more important than ultra precise charge weights................

Pete

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