Primer testing methods

How are people testing primers? I've seen several methods:

1. Shoot a 10 round ladder test over a chrono and look at the stability of the curve.

2. Load 3 rounds of your preferred charge with a different primer: -0.5gr, +0.0gr, and +0.5gr. Shoot them over a chrono and see if ES/SD improve.

3. Shoot groups with each primer and compare the sizes.

And finally some more questions:
What is your preferred method?
Will a specific powder have a preferred primer?
Is a good primer a good primer and will work well regardless of other variables?
Can a primer with poor stats group better than one with superior stats?

Test parameters:
1 - Make sure primer is not Winchester.
2 - Pull trigger on loaded case, if it goes bang, test complete.

@Magnetite, kinda depends on what you want to achieve.

For most shooting (service rifle, gongs, hunting) I just load using Federal.

When I shot fullbore and was looking for the last ounce off accuracy, I did full load dev with 3 different primers. They can make a surprising difference to your SD values. RWS primers were by far the best I tested, followed by Fed Match and CCI BR.

In general, powder and or primer will give you speed consistency. Seating depth gives you group size variation within that.

Quote:

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Originally Posted by 257weatherby

1 - Make sure primer is not Winchester.

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Please elaborate on step 1.

Quote:

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Originally Posted by Magnetite

Please elaborate on step 1.

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Couple years back Winchester primers had some quality control issues. Lot of people ended up with gas cut bolt faces.

Use them at your peril.

Just hit it with a hammer

Quote:

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Originally Posted by ebf

Couple years back Winchester primers had some quality control issues. Lot of people ended up with gas cut bolt faces.

Use them at your peril.

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+1 would never use a Winchester primer again.

Federal match in SR and LR. CCI 250? mags, job done.