In the video the primers were only weighed in grains rather than grams but it does support the idea that primers of consistent weight will produce more accurate loads.
As myself and others have suggested, weighing in grams is much more accurate and able to determine weight variance to a finer degree and if his primer weight had been in grams with a variance of say .002 grams his target results would have been showing even better results.
Here is a better video explaining the variance that can be seen with the difference between primer weights:
and this follow up:
Thanks for the recommendation of weighing in Grams
(Actually milligrams)
Grams didn't make sense to me when grains is a finer measurement
But when I realized you must have meant milligrams it all made sense then
So I broke out my Gemini 20 - nice little scale I bought years ago
The batteries are still good even, cant believe it, nice blue backlit display, stays zeroed, doesnt drift.
Anyway, it has several different scales but the finest resolution is in Carats, or milligrams
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Opened up a WHOLE NEW WORLD compared to weighing in grains.
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Biggest Eye Opener is
There is good reason to pay more for MATCH primers like GM-210 and BR-2
More useable primers of the same weight and less outliers
BR-2's were nearly all the same weight, amazing!
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Another eye opener - my 115 DTACS are WAY closer together in weights than Bergers
Maybe 5 mg spread for 50 bullets with 3 extreme outliers out of a quick 50 that I sorted
Some BENCHREST Bullets are not much closer in charge weights than normal brands like
Sierra
Lapua Scenar 6mm 105s' were all over the place, very disappointed in those
Some other brands are like 30 miiligrams apart for the same bullet!!!
WOW,
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Anyway
Q. I am sorting bullets to within 5 milligrams (+/-2.5 mg)
and Primers to within 3 milligrams (+/- 1.5 mg)
do you believe this is close enough spread to batch them in?