Two primers different results

Alex Wheeler

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Primers can make or break a load. Far more critical than most give them credit. Especially in the larger cases. Round robin has its place but not in group shooting. I think you may find better results shooting your group with at least some improvised wind flags if your not already. I have usually found good results with fed 215s or cci 250s with h1000
 

Rich Coyle

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For years I have been doing round robin when there is more than one group to be fired. I use a flag about ten feet from the muzzle attached to the sky-screen rod of the Oehler 33. It is made from a long strip of light grocery plastic bag an inch wide. There was a 12 o'clock breeze maybe one or two miles per hour yesterday. I had five different primers loaded yesterday but didn't get to the range until 10AM. Today, Lord willin', I will get there at 8AM. I will reshoot the 9 1/2M along with 215's, 250's and BR-2. If I don't post you can guess I didn't duplicate.:)
 

Alex Wheeler

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Round robin is good for ladder tests to try a spread condition changes out over the whole ladder, which should be fired as fast as possible. If your shooting groups, round robin is going to induce so much more condition related error in your groups. I highly recommend shooting each group in a condition and as quick as possible to mitigate condition changes. Its not just wind, lighting and other environmentals that change play a role. When testing primers, they can take you out of your accuracy node. So once you have tested them all, you need to see the velocity changes they caused, then go back and adjust powder charges to bring each of them back into the accuracy node. Then shoot them again. Obviously if a primer changes velocity 30 fps its not going to group as well as the one you tuned the gun on. But it may shoot better if you adjust the powder to bring it back.
 

gohring3006

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Weight sorted cases?
Annealed?
Flasholes deburred?
Shooter error?
Warm chamber/barrel vs. cold chamber/barrel? Temp consistency?
Sorted bullets by weight/length?
All test need a positive standard. What’s the standard?
 

Rich Coyle

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I use a laser temp gauge and don't fire the next round until the barrel right in front of the fore end is below 80 degrees. No weight sorting. None have been annealed. Flash holes deburred. I liked every hold. No bullet sorting.

I have no idea what you mean by "a positive standard".
 

gohring3006

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I use a laser temp gauge and don't fire the next round until the barrel right in front of the fore end is below 80 degrees. No weight sorting. None have been annealed. Flash holes deburred. I liked every hold. No bullet sorting.

I have no idea what you mean by "a positive standard".
Well... do you have a load that shows the capability of the rifle?
How do you know the velocity variance and fliers isn’t from inconsistent brass capacity? How do you know it wasn’t from inconsistent neck tension?
How do you know it wasn’t from inconsistent bullet length/weight?
Positive standard should be,
Same weight sorted brass annealed effectively should be used every time, bullets sorted for weight length, and chamber/barrel temp kept the same. If not, then there can be reasonable doubt in your test.
 

gohring3006

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Primers absolutely have a affect on loads, but so does all the things I listed.
At the end of the day, the test has to satisfy the tester. It’s seems that it has.

But questioning results, always brings better results.
 

Mike 338

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Unless I stumble onto a great load first time out, I test various primers. About 60% of the time, there's no appreciable difference but sometimes the difference is amazing.
 

RockyMtnMT

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Good friend of mine just texted me from the range. He is developing a load with our 199g Hammer Hunter in his old wore out 300rum. He worked up to 92g rl25 with an es of 6 for 5 shots and sub one inch at 100y with a vel of 3200fps. He had to leave the range because it was filling up with idiots. I think that was a quote. No pressure signs. I think he can probably get a grain or two more, but he may just call it good.

Point here is there was no sorting, particularly the bullets. He is meticulous about brass prep and charge weights, primer seating, and bullet seating. This is the 1st time he has loaded Hammers for his rum and he has never had that low of es. He is well under 20 rounds of load dev. Only reason he has shot as many as he has is because he shoots 5 shots with each charge. I only shoot one. I rarely get es over 20fps and often see single digit. When using Hammers brass is the weak link.

Steve
 

gohring3006

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That’s awesome Steve.
I can see where monos would have very tight tolerances.
 

RockyMtnMT

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That friend is mtmuley that is frequently on lrh. Hopefully he will see this and chime in. He can give a better account of his loading technique.

Steve
 

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