Load testing

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Load testing

Postby Cutright » Wed Mar 01, 2017 2:01 pm

Just curious on everyone's load testing procedures. Three or five shot groups, fouling shots, how often barrel is cleaned, cooling barrels, testing different aspects of the same load (length, primer, crimp), and any other aspects.
Cutright
 
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Re: Load testing

Postby Hoot » Wed Mar 01, 2017 9:53 pm

Cutright wrote:Just curious on everyone's load testing procedures. Three or five shot groups, fouling shots, how often barrel is cleaned, cooling barrels, testing different aspects of the same load (length, primer, crimp), and any other aspects.


Everyone has their method. Here's mine.

I start with a cleaned, dry patched barrel and fire a couple of foulers. I then shoot my 5-shot group.
Given the barrel will slowly foul, if I have say 4 different loads I'm testing, I shoot them round robin, so that they all share in the impact that gradual fouling might have.
IE: 1A 1B 1C 1D, 2A 2B 2C 2D, 3A 3B... etc
If I have more than 4 loads I'm testing, I shoot the 4 groups of 5 shots and re-clean, dry patch. Shoot a couple more foulers, then do the next batch.
When I'm fast-tracking a powder experiment just for the velocities, I sometimes only shoot 3-shot groups to get my max load and baseline accuracy established. I come back another day with the narrower selection of powder steps using 5-shot groups. Even 5-shots groups are statistically pretty insignificant, but its where I draw the line in this caliber.

There are range days where after a few shots, its pretty apparent that I'm not on my game in terms of what my shooting skills are doing to my groups. If I'm there to test for accuracy of the load, not me, I'll either go home or take out the Lead Sled, to remove me from affecting the results. I have that latitude since I live 10 minutes from the local club and I'm the Rifle Range Coordinator. My second home. ;)

I know precision shooters who devote their time to precision rifles who would scoff at only a 5-shot group. Some of them consider 20 shots to be a statistical minimum and often one of them a day, over the course of several days worth of differing weather conditions, especially temperature. There's a place for that degree of fastidiousness. This caliber doesn't see much in the way of competitive shooting however. 5 shots satisfies me. There is an argument for not developing a pet load when its 80 degrees out if you're going to be using it when its 25 degrees out and vice versa. Ball powders like this caliber prefers change with temperature.

EDIT: I learned this the hard way. Never change powder lots in the middle of a testing experiment. If you don't think you will have enough powder left in the bottle, don't start. Get another bottle first. Use the remnants from the first bottle for foulers. That's why frequent experimenters buy larger quantities at a time. Ditto on pulled bullets. Use them for foulers or fun shooting.

Hoot
In Theory, there is no difference between theory and practice. In Practice, there is.
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Re: Load testing

Postby Cutright » Thu Mar 02, 2017 3:54 pm

Thanks Hoot. I like the round robin idea. I haven't thought of that, but will certainly incorporate this in the future
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