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Very Hot Topic (More than 25 Replies) PRIMER CHOICE (Read 1464 times)
joeb33050
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PRIMER CHOICE
Apr 24th, 2019 at 9:31am
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PRIMER CHOICE

There are a few questions.

Are small primers more accurate than large primers?

Does firing pin strike force variation vary accuracy?
We have the report of Charlie Dellís test, saying NO. Stevens 44 1/2 rifles, Iím told, have adjustable firing pin force. Testing is simple.

Does primer choice affect accuracy?
My experience and testing says NO, that either the primer sets off the powder charge, or it doesnít. If the gun fires, accuracy does not vary with primer choice.

My test results for primer choice with cast and jacketed bullets are not satisfactory, other variables are included and/or sample sizes are too small.

A search of the internet found no reports of reasonable tests. There are reports about brisance and primer energy and cup dimensions and anvil location; but the reports that I found connecting primer choice and accuracy have distressingly small sample sizes.

One of the reports counts primer choice in loads recommended by competent shooters. This seems to be a reasonable though fuzzy way to look at the question, so I did.

CBA NM primer choice, by place, (1 = first, 2 = second,Ö).

  
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joeb33050
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Re: PRIMER CHOICE
Reply #1 - Apr 24th, 2019 at 9:34am
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These tables suggest that there is no much-more-accurate primer, else it would appear in greater numbers. Unfortunately, this suggestion is based on the assumption that the shooters have conducted tests, which may be/probably is, false.

It is NOT possible to prove that there is NO shooter/bullet/gun combination that shoots smaller groups with one primer than another.

If a shooter/bullet/gun combination IS found that shoots smaller groups with one primer than another, with reasonable sample size; then we can examine the better primerís characteristics and perhaps make progress toward improved accuracy.

So, Iím looking for tests and test reports, with a reasonable sample size, showing that primer A shoots more accurately than primer B. A reasonable sample size is five, 5-shot, 100-yard groups.
(All other data is on castbulletinfo, a yahoo group.)
  
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JLouis
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Re: PRIMER CHOICE
Reply #2 - Apr 24th, 2019 at 10:40am
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A rifles precision is derived from the correct combination of several components coming together as a successfuly completed unit. Accuracy is soley derived by individual shooter abilities. Where one places in a match is determined by both precision and accuracy. Powder choice can determine the correct primer choice. Example Ball Powders are harder to ignite and the wrong primer choice will leave unburnt powder in the barrel. Unburnt powder can directly effect a rifles precision as can all of the individual components one chooses to use.
  
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Dellet
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Re: PRIMER CHOICE
Reply #3 - Apr 24th, 2019 at 11:57am
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joeb33050 wrote on Apr 24th, 2019 at 9:34am:
These tables suggest that there is no much-more-accurate primer, else it would appear in greater numbers. Unfortunately, this suggestion is based on the assumption that the shooters have conducted tests, which may be/probably is, false.

It is NOT possible to prove that there is NO shooter/bullet/gun combination that shoots smaller groups with one primer than another.

If a shooter/bullet/gun combination IS found that shoots smaller groups with one primer than another, with reasonable sample size; then we can examine the better primerís characteristics and perhaps make progress toward improved accuracy.

So, Iím looking for tests and test reports, with a reasonable sample size, showing that primer A shoots more accurately than primer B. A reasonable sample size is five, 5-shot, 100-yard groups.
(All other data is on castbulletinfo, a yahoo group.)


I think you have changed your premise.

The original question was basically will changing only  primers likely change group size or point of impact. To which you suggest it will not.

Your data to back that up is showing that top shooters/loaders are able to make any primer work well.

The test I think you are looking for is where someone has taken their national match winning load that uses small primers, cut half the primer pockets to fit large.

Then used the exact same load data randomly selecting primers of as many different part numbers as possible, based only on will they fit the pocket.

Your premise is that group size and or point of impact will not change.

Is that correct, or did I miss the point?
  
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kkid66
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Re: PRIMER CHOICE
Reply #4 - Apr 24th, 2019 at 12:03pm
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A Sharps will still go bang with a broke firing pin but accuracy will suffer greatly. Had the same thing happen with my C-sharps 85.
  
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JLouis
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Re: PRIMER CHOICE
Reply #5 - Apr 24th, 2019 at 2:17pm
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How I might feel based on my own personal test results can be and should be totally useless to anyone else. Each individual should go out and do his or her own personal tests and to then decide for themselves. That way it is solely based on their own individual test results and will not be miss-leading if depending on someone else's.



  
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oneatatime
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Re: PRIMER CHOICE
Reply #6 - Apr 24th, 2019 at 4:42pm
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There is no magic formula. For any primer, any bullet, any powder, any rifle, and let's not forget, any loader/shooter there will be certain combinations that work better than others. That said, it becomes fairly common knowledge that a few certain powders require a certain level of primer to work as well as they can.
  
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craigd
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Re: PRIMER CHOICE
Reply #7 - Apr 25th, 2019 at 2:03pm
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Not primer specific, but 22lr shooting can show how presumably very subtle differences can make accuracy differences. One lot of supposedly identical ammo may shoot measurably different than another lot. Maybe, the easiest place to look for accuracy affecting data from primer differences might be with the jacketed bullet benchrest shooters.
  
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rafter3c
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Re: PRIMER CHOICE
Reply #8 - Apr 25th, 2019 at 2:54pm
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Back in 1983 Connie Grimes found that a certain lot of Win 8 1/2 X 120 LR primers were of match quality. I asked that around 10,000 of these primers be purchased for me. I picked them up at the next Coors Schuetzenfest that year. I am not sure how much these primers helped my scores over the following years but mentally it was a big help. Having a inline coil main spring striker action along with the 8 1/2 X 120 primers proved to work well.
There are BR shooters here on this Forum that I would look to for information as to best primers.
KL† †
« Last Edit: Apr 25th, 2019 at 3:28pm by rafter3c »  
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JLouis
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Re: PRIMER CHOICE
Reply #9 - Apr 25th, 2019 at 4:42pm
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Totally agree Ken and as BobZ noted here or in another thread there was a batch of the White Box Winchester Large Rifle primers that far exceeded anything then or since for my use.
  
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Dellet
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Re: PRIMER CHOICE
Reply #10 - Apr 25th, 2019 at 9:33pm
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craigd wrote on Apr 25th, 2019 at 2:03pm:
Not primer specific, but 22lr shooting can show how presumably very subtle differences can make accuracy differences. One lot of supposedly identical ammo may shoot measurably different than another lot. Maybe, the easiest place to look for accuracy affecting data from primer differences might be with the jacketed bullet benchrest shooters.


One of current debates with the big kids, is how much tighter your ES is when you weigh and batch your primers, and how that effects your groups at 1000 yards.

Then again when you can shoot a 1Ē group at 600 yards thereís probably a lot of subtle differences you can tell me about that I am not likely be able to experience.
  
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Schuetzendave
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Re: PRIMER CHOICE
Reply #11 - Apr 26th, 2019 at 5:13am
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Rifles I have tested had smaller group sizes but slighly larger ES.

Once you have a good powder load reducing the ES will not improve accuracy.

I have found increasing or decreasing my powder load by a tenth grain will find a powder sweet spot with lower barrel vibrations that produces tighter group sizes but ussualy increases the ES by a couple of points.

So once your ES is below 10 fps difference; reducing it may not improve your accuracy.

Slight changes in powder load to reduce barrel vibrations will enable you to obtain better accuracy.

I have found there is a powder sweet spot about every 0.3 grains of powder. But then you need to find the best sweet spot which means testing higher and lower sweet spots to find the tightest group your rifle can be fine tuned to.

I do this by shooting 30 shot groups to test between loads.

And every time you change your primer then you need to retest your powder load to find the right sweet spot again.
« Last Edit: Apr 26th, 2019 at 6:45am by Schuetzendave »  
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Dellet
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Re: PRIMER CHOICE
Reply #12 - Apr 26th, 2019 at 10:59am
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Schuetzendave, your targets really could almost prove the point of sorting primers had you weighed them, or not.

Target #2 has a random high flyer, target #4 has vertical string. Both if caused by velocity, would be somewhere around 10 fps.

If targets 1,3,5 had matching primers, it would be a good indication, but those three targets are almost too good to get any useful information, other than to rule out shooter error on targets 1&2.

Maybe a longer distance shot, more of a pattern could be seen?

There has been more and more discussion in the last few years in the long range crowd and group sizes are shrinking.

Here's one persons target at 600 yards with primer weights listed and a link to the thread.

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Why is it that people that cast and sort bullets to a 1/10 of a grain, powder to 1/100 of a grain have trouble thinking that sorting primer charges(because that's really what you are doing) might make a difference?

For a disclaimer, I probably don't shoot consistently  enough to have my targets have much meaning compared to yours. What I can say is that I shoot a reasonable amount of different disciplines, reasonably well. The resistance of one style of shooting to accept a different idea from another, seems to be the only universal truth.

I am a ways from likely being able to see the difference sorting primers can make, doesn't mean I can't learn something now about quality control and if it might matter.
  
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JLouis
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Re: PRIMER CHOICE
Reply #13 - Apr 26th, 2019 at 12:43pm
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Sorting primers by weight is a daunting task and depending on brand one can end up with numerous various weights / lots. I once went through a thousand and ended up with four and only one with enough to get me through very few practice outings and a few matches. With that being said I have found indexing the primer and having the anvil properly set back into the cup to be the more beneficial approach and a heck of allot easier.
  
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Schuetzendave
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Re: PRIMER CHOICE
Reply #14 - Apr 26th, 2019 at 2:40pm
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Niether the bullet, powder or primer were weighed.
The bullets were made from scrap lead from the metal recycler and the tin was waste 30% alloy from a radiator shop.
These targets were not shot on a calm day.
The changes of bullet hits on the target were 100% wind effects; quick changes in velocity or direction, or slight changes I did not anticipate or correct for.
I cannot place blame for shot placement; on the equipment, when shot placement was due to the shooter's call of the wind.
If I had fired in an enclosed range those slightly off shots would not be there - unless it was due to bench technique (very small chance since I was the International Benchrest Champion - twice).

After shooting over 200,00 rounds of Remington 7 1/2 primers I have found them to be exceedingly consistent and have found no need to sort them.

For accuracy I do uniform all my primer pockets and the inside flash hole as well; plus I clean out the primer pockets after each firing.

Early in my shooting career I weighed everything; but a very long shooting experience has told me: IT DOES NOT MATTER.

Commercial ammunition manufactures state any ammunition component that has less than 1% weight deviation is MATCH grade ammunition and you will not have SIGNIFICANT changes in accuracy by sorting.

To find the sweet spot your powder load has to be precise to a tenth grain.
I have selected an appropriate powder (fine small ball) that can be precisely dropped from a powder measure by developing techniques to drop powder loads without variations in weight.

I could spend all my time trying to get better groups but I rather go have fun shooting and socializing with my friends.

1/2 MOA in this game is good enough for me - I will leave it up to the younger crowd to find the improvements for their generation.
« Last Edit: Apr 26th, 2019 at 3:16pm by Schuetzendave »  
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