same load different groups???

trapoholic

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What happened?! Everything is exactly 100% the same as always. New Remington 30-06 brass, federal gold medal match 210 large rifle primers, reloder 16 powder. Only thing that changed was the lot number of the powder. 2" groups, my old loads with everything the same still shoot 1/4". What's goin on?!
 
The shooter maybe? Lot to lot variation can be fairly significant as well...

I'm gonna give it a go again tomorrow and hope it was the shooter but I doubt it. Walked back from the target and immediately fired 4 shots of last year's loads and it went back to 1/4". Everything being carbon copy minus new bag of brass and lot # of powder.
 
Is the brass from the same lot?

No idea. The cases do seem "fuller" with 55 grains than the last bunch though. Should I just load up my last once and twice fired brass from the first work up? It'll be the same poi as before with the original load with that brass ya? This guns been real fussy from the get go. I've got other gun with brass on it's 6th reload that still shoot the same as it did new. But this gun I really fear deviating from what originally worked. Know what I mean? Anybody else got a gun like that?
 
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Neck tension inconsistencies can affect accuracy for sure but when I tested neck tension vs velocity on various degrees of crimped/no crimps the MV didn't change. Try it.
 
Neck tension inconsistencies can affect accuracy for sure but when I tested neck tension vs velocity on various degrees of crimped/no crimps the MV didn't change. Try it.

I had to buy an external hard drive to store all my chronographing data throughout the years. Been there, done that ad nauseum. Google H110 crimp and fill your boots. Plenty of powders are affected by the level of crimp. Some profoundly.
 
Guess I forgot to mention I do crimp everything. Crimp hasn't changed at all. But I'll drop down to 53.5 grains tomorrow and work up. More info is appreciated though. 3" higher than the last batch should have raised a red flag as far as increased velocity goes
 
Different batch of brass could also have different volume. I'm currently using two different batches of Nosler 7mm RM brass that have 2 grains of H2O internal volume difference. Annoying to say the least.

As for the powder, I found that if you allowed your old powder to dry out in any way, the fresh powder will be slower. Something about fresh powder having a higher moisture content. Something Ganderite taught me in a different thread of mine.
 
The difference could to related to a number of issues. Check your scope mounts to assure that they are tight.
 
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