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Very Hot Topic (More than 25 Replies) PRIMER CHOICE (Read 3923 times)
Schuetzenmiester
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Re: PRIMER CHOICE
Reply #15 - Apr 27th, 2019 at 7:49pm
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Dave, What kind of equipment were you shooting against?
  

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Schuetzenmiester
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Re: PRIMER CHOICE
Reply #16 - Apr 28th, 2019 at 1:45pm
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OK, thanks, I thought International Bench Rest might be another association like  NBRSA.  Huh
  

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Pentz
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Re: PRIMER CHOICE
Reply #17 - Apr 28th, 2019 at 10:59pm
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So...As I was "called out" herein by not subscribing to the proposition that all primers are created equal, or... brand of primer does not affect accuracy.  That proposition made it over to another forum as well; here's my test:

The test: five, 5-round groups fired at 100 yards from my 1917 Winchester Mod Scope rifle, in a Boyd sporter stock with an Athlon Midas BTR Gen 2  30 mm scope, 4.5-27x.  Powder was 17.5 grains of 2400 weighed, under bullets sorted to 0.5 grain, and cast 22 bhn, from a mold made for my throat and barrel.  The rear band measures .311, the nose .302 that is engraved by the rifling at 3.35 COL when chambered.  The barrel was a virgin 1919 NOS 5-groove when I purchased it and has never seen a jacketed bullet.  The cases are LC 67, weight sorted to within 1 grain, trimmed and neck turned, with reamed flash holes; this lot has been fired 23 times with periodic torch annealing.

Primers tested were Remington 9 1/2 and 9 1/2M, Federal 210, Winchester LR, and CCI 200 seated just below flush with a Frankfort hand primer.  I did not use any large pistol primers.   I used the 27x setting, and fired over a front rest and rear bag with a very hard hold.  Weather was balmy in the low 60s, variable light breezes, and the grass was 2.5 inches high.  I was too lazy to set up my chrony, gonna have to budget a LabRadar some day.

After zeroing, five, 5-round groups were fired, the results are shown on the enclosed target.

Remington 9 1/2    - 2.20" by 1.63" group

Remington 9 1/2M - 2.65" by 1.78" group

Federal 210 -           0.88"  by 0.72" group

Winchester LR -      0.80" by 0.76" group

CCI 200 -                0.69" by 0.29" group ( I pulled the last round at 2clock)

Conclusion:  While this was not a statistician's 100 round group test, I'm not going to cast up 500 weight-sorted bullets to do so - the differences between brands of primers are obvious.  My rifle prefered Remington 9 1/2 primers when using my stash of 4759; grouping went to pot with 2400.  Clearly, I'm using CCI 200s with 2400 for now.

Yeah, it was a repeating rifle, but the effects are still apparent.
Flame away.... Roll Eyes

  

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Schuetzenmiester
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Re: PRIMER CHOICE
Reply #18 - Apr 29th, 2019 at 12:02am
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Does that primer test really prove anything if the load is not tuned for each primer?
  

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craigd
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Re: PRIMER CHOICE
Reply #19 - Apr 29th, 2019 at 8:20am
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Schuetzenmiester wrote on Apr 29th, 2019 at 12:02am:
Does that primer test really prove anything if the load is not tuned for each primer?

If all else is truly equal and repeatable, doesn't that show how one component might affect accuracy? While it might not pan out, I know which load of the targets shown I'd want to look into fine tuning.
  
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joeb33050
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Re: PRIMER CHOICE
Reply #20 - Apr 29th, 2019 at 10:52am
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PENTZ; would you please measure and post the group sizes, center to center?
Thanks;
joe b.
  
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Pentz
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Re: PRIMER CHOICE
Reply #21 - Apr 29th, 2019 at 11:15am
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Groupd center to center are posted on the target and in the text.
  

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JLouis
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Re: PRIMER CHOICE
Reply #22 - Apr 29th, 2019 at 11:17am
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Craigd that is the approach that I have always used. Once I have found the Primer that is continually providing the best groups and fine tune it from there. One also has to be careful if changing lot numbers as they might not provide the same results as the last batch.
  
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Schuetzenmiester
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Re: PRIMER CHOICE
Reply #23 - Apr 29th, 2019 at 12:06pm
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craigd wrote on Apr 29th, 2019 at 8:20am:
Schuetzenmiester wrote on Apr 29th, 2019 at 12:02am:
Does that primer test really prove anything if the load is not tuned for each primer?

If all else is truly equal and repeatable, doesn't that show how one component might affect accuracy? While it might not pan out, I know which load of the targets shown I'd want to look into fine tuning.

It certainly does show there is a big difference.  The others potential remain an unknown until tested.
  

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Re: PRIMER CHOICE
Reply #24 - Apr 29th, 2019 at 12:32pm
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Schuetzenmiester wrote on Apr 29th, 2019 at 12:06pm:
craigd wrote on Apr 29th, 2019 at 8:20am:
Schuetzenmiester wrote on Apr 29th, 2019 at 12:02am:
Does that primer test really prove anything if the load is not tuned for each primer?

If all else is truly equal and repeatable, doesn't that show how one component might affect accuracy? While it might not pan out, I know which load of the targets shown I'd want to look into fine tuning.

It certainly does show there is a big difference.  The others potential remain an unknown until tested.


I think what it shows is the order in which to pick or change components.

You really have no adjustment with a primer, only replace. You can change powder charge, seating depth, to some extent bullet weight with cast.

In short you can tune a load to the primer, but you can't tune the primer to the load.

The posts that show a variety of primers can win matches support that idea.

The posts that show greater group dispersion only changing primers, support that some primer/powder combinations work better, or have a larger, more forgiving sweet spot.

  
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joeb33050
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Re: PRIMER CHOICE
Reply #25 - Apr 29th, 2019 at 12:57pm
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I can't find any group size, one measurement, center to center of the 2 furthest-apart holes. I see -2.20" X 1.63", don't know what that means.
joe b.




Pentz wrote on Apr 29th, 2019 at 11:15am:
Groupd center to center are posted on the target and in the text.   

  
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