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Very Hot Topic (More than 25 Replies) PRIMER CHOICE (Read 4636 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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JLouis
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Re: PRIMER CHOICE
Reply #8 - 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 #9 - 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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Dellet
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Re: PRIMER CHOICE
Reply #10 - 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.

(You need to Login or Register to view media files and links)

(You need to Login or Register to view media files and links)


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 #11 - 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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Schuetzenmiester
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Re: PRIMER CHOICE
Reply #12 - Apr 27th, 2019 at 2:33pm
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Dave, What did you shoot in the  International Benchrest Championships?
  

"some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence
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Schuetzenmiester
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Re: PRIMER CHOICE
Reply #13 - Apr 27th, 2019 at 2:34pm
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Dave, What did you shoot in the  International Benchrest Championships?
  

"some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence
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MikeK
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Re: PRIMER CHOICE
Reply #14 - Apr 27th, 2019 at 6:52pm
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The following data was originally posted on Sigforum.  It shows that for a revolver cartridge, the .327 Federal, the choice of primer is critical.

I have a Ruger Single Seven in .327 Federal with the 7.5" barrel. I have found that loading the .327 Federal presents some challenges, namely dealing with large extreme velocity spreads, 150-200 fps.

Brian Pearce wrote an article about the .327 Federal in Handloader magazine, issue 294 (Feb-Mar 2015) and answered some questions I asked in issue 312 (Feb-Mar 2018) about reloading issues with the 327.

Based on his comments regarding primer testing I decided to run some comparisons of a variety of small pistol and rifle primers in the .327 Fed.

The load was 11.0 gr 2400, in Starline brass. Bullet was the Hornady 100 gr XTP. Cases were trimmed to the same length, primer pockets and flash holes uniformed, and a firm roll crimp was used.

I compared 10 different primers. Fifteen shots were fired with each primer. Velocity was measured 15 feet from the muzzle.

CCI 500
Velocity: 1451 fps
Extreme Spread: 179 fps
Standard Deviation: 60.1 fps

Federal 100
Velocity: 1379 fps
Extreme Spread: 74 fps
Standard Deviation: 20.3 fps

Federal 200
Velocity: 1352 fps
Extreme Spread: 74 fps
Standard Deviation: 21.2 fps

CCI 550
Velocity: 1443 fps
Extreme Spread: 163 fps
Standard Deviation: 56.0 fps

Federal 205M
Velocity: 1360 fps
Extreme Spread: 50 fps
Standard Deviation: 18.0 fps

Winchester WSP
Velocity: 1357 fps
Extreme Spread: 44 fps
Standard Deviation: 13.7 fps

Winchester WSR
Velocity: 1360 fps
Extreme Spread: 69 fps
Standard Deviation: 21.9 fps

CCI 400
Velocity: 1365 fps
Extreme Spread: 138 fps
Standard Deviation: 33.5 fps

CCI 450
Velocity: 1455 fps
Extreme Spread: 73 fps
Standard Deviation: 19.6 fps

CCI #41
Velocity: 1370 fps
Extreme Spread: 140 fps
Standard Deviation: 37.5 fps

Of all of these, the second to the last one, with the CCI450 gave the best results, giving the highest average velocity, with the lowest pressure signs, as determined by primer appearance and ease of case extraction along with good accuracy. One other thing I had noticed - the muzzle blast and flash often varied a lot among the same load, with some giving a much louder report and large flash, with others being not as loud and little flash. The quieter less flashy loads gave the highest velocities. All 15 of the rounds with the CCI 450 primer were like this, no big blast or flash.

The Federal 205M and Winchester WSP gave similar results.
  
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