rjtfroggy
Gold $$ Contributor
Those who sort primers by weight...Have nothing better to do with their time.
Those who sort primers by weight...
- Thread starter kelbro
- Start date
CCI 450 & CCI BR sorted primers. One lot of 2900 and the other 8000 primers. All sorted on a Sartorius Entris scale, with a resolution of .002 grains. These were sorted using only the first two decimal places. The 450's varied from 3.59-3.78 grains, The BR's varied from 3.62-3.83 grains. The far left column is the percentage of each weight observed. I weigh powder charges to the kernel (.02 grains). There is no possible way that I will accept the primers to vary in "charge weight" by up to .29 grains. Yes, that would take some extremely bad luck, but any controllable variable should never be overlooked. And NO, the variations are NOT in the cups or anvils.
Lane
Lane
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ISS
Gold $$ Contributor
I was 76 in late September last year. I do not have enough time left to weigh primers. It's enough to weigh bullets and brass. Never found that to hit or miss a Rockchuck even at extended yardages since the little buggers never stand still more than a couple seconds. About 10% of them stand or lay still.
Especially those of you who weigh by grams (over 15grains). It seems a coarse limit. Grains there might be an excuse to when Spartan Precision Rifles/Alex Sitman/Bc'Z finish my rifle.
Especially those of you who weigh by grams (over 15grains). It seems a coarse limit. Grains there might be an excuse to when Spartan Precision Rifles/Alex Sitman/Bc'Z finish my rifle.
ISS
Gold $$ Contributor
A separate thought after reading and rereading all of these posts. Still confused, but have a question for the serious sorters. How much weight and bore diameter difference in the carbon/jacket fouling in the barrel is there after each shot? That has to count as much as .001gr weight difference.
Bottom Fodder
Silver $$ Contributor
Which takes longer weighing 1000 primers or readying all the post on weighing primers
.002 grain equaling .00013 grams…
I still think that weighing with the scale set to grams {in my case an A&D i120} gives a better discernment value than weighing in grains…
It will weigh grams to .001 = .0154 grains.
Unless of course you have the above mentioned Satorius that will go to .002 grains over most scales only being able to weigh grains to .02 = .0013 grams
tom
Gold $$ Contributor
Liven The Dream
Gold $$ Contributor
As Pointed out age ! 79 3/4 .
I have some 450's from 2021 and now 2026.
I am going to weight test them by date to see any difference ?
Weather permitting a 600 yard e-Target can be done. 6 Dasher or 6GT will be the Rifle used.
F/Open style shooting.
Hope to get started this week will go for grams on FX120i
I have some 450's from 2021 and now 2026.
I am going to weight test them by date to see any difference ?
Weather permitting a 600 yard e-Target can be done. 6 Dasher or 6GT will be the Rifle used.
F/Open style shooting.
Hope to get started this week will go for grams on FX120i
RickyK
Gold $$ Contributor
Thats Me !
Retired shooter
Gold $$ Contributor
You would probably have to be a top level shooter and shoot in a tunnel to see the difference. One of the posters put up data that showed there is a difference in charge weight. If you collect chrono or target data it's easy to assume the differences are caused by what you want them to be. Do the top national shooters weigh primers or just internet people.
Can a few guys on this website that shoot at National events comment on your opinion on primers.
The video doesn't show how the foils are inserted.
How Primers Are Made — Video from Federal Factory « Daily Bulletin
Do you know how gun primers are made -- how the explosive elements are applied into those tiny cups? Find out by watching this video filmed at a Federal ammunition factory. It starts out with empty primer cups loaded, 1000 at a time, into trays using vibration (0:05 time-mark).
But if you are the competitive type......
The video gives 17 fps end to end for sorted primers in a 2680 fps 308.
If we compare that to weighing bullets, let's start with something comically large for the unsorted like 1 grain on the 200 grain bullets in the video. The first cut at it is by kinetic energy, the velocity will change with the square root of the weight differences. Using his nominal 2680 fps;
2680 * sqrt(200/201) = 2673 for a difference of 7 fps. With a difference in bullet weight that would be an unlikely outlier.
The QL estimate is only 4 fps because the peak pressure increases 300 psi with the heavier bullet.
The target will see even less than the 4 fps because the BC goes up with weight further reducing the velocity effect.
Abusing his numbers some more;
Starting with a nominal SD of 8 and estimating the effect of rolling back in an even distribution of that 17 fps ES, call it a SD of 6 fps, we get:
(8^2 + 6^2)^1/2 = 10, so the unsorted primer SD would go from 8 to 10.
That's an RMS estimate, it's not going to happen every time. It'd be likely as not to be noticed when comparing two five shot groups.
Like the bullet weight, there are other factors that would reduce the observed effects. The largest is about 2/3 of the weights tend to be clustered in the middle. The likelihood that a 5 shot group would have both a heavy and light primer is low.
Weighing primers isn't for everybody, definitely not if you're trying to minimize time at the loading bench, but it isn't the meme it's been made out to be either.
The video gives 17 fps end to end for sorted primers in a 2680 fps 308.
If we compare that to weighing bullets, let's start with something comically large for the unsorted like 1 grain on the 200 grain bullets in the video. The first cut at it is by kinetic energy, the velocity will change with the square root of the weight differences. Using his nominal 2680 fps;
2680 * sqrt(200/201) = 2673 for a difference of 7 fps. With a difference in bullet weight that would be an unlikely outlier.
The QL estimate is only 4 fps because the peak pressure increases 300 psi with the heavier bullet.
The target will see even less than the 4 fps because the BC goes up with weight further reducing the velocity effect.
Abusing his numbers some more;
Starting with a nominal SD of 8 and estimating the effect of rolling back in an even distribution of that 17 fps ES, call it a SD of 6 fps, we get:
(8^2 + 6^2)^1/2 = 10, so the unsorted primer SD would go from 8 to 10.
That's an RMS estimate, it's not going to happen every time. It'd be likely as not to be noticed when comparing two five shot groups.
Like the bullet weight, there are other factors that would reduce the observed effects. The largest is about 2/3 of the weights tend to be clustered in the middle. The likelihood that a 5 shot group would have both a heavy and light primer is low.
Weighing primers isn't for everybody, definitely not if you're trying to minimize time at the loading bench, but it isn't the meme it's been made out to be either.
My testing results mirrored what the video above found. It works out to roughly 1 fps per .01 grains difference. With the wide variations in weight, that is substantial vertical variations at 1000 yards, simply due to big ES. It takes all of 15 minutes per 100 to sort primers. The more one begins with, the bigger each individual pile will be. For international matches, I will load every single round from only one or two piles from the center of the bell curve. The oddballs all get used for fouling and early sighters. For local matches, start at one end and work towards the middle. In the lot of 8000, the F-Open guns start at one end of the bell curve. The F-TR guns and Palma rifle start at the other end.
Something that struck me about some of the previous comments, is that sometimes we fail to realize that not everyone on this AccurateShooter site is concerned with getting the Nth degree of accuracy out of their equipment. Those of us who compete and expect to at least have the opportunity to win every single time out don't really have the option of foregoing these details. At 1000 yards, EVERYTHING matters.
Lane
Something that struck me about some of the previous comments, is that sometimes we fail to realize that not everyone on this AccurateShooter site is concerned with getting the Nth degree of accuracy out of their equipment. Those of us who compete and expect to at least have the opportunity to win every single time out don't really have the option of foregoing these details. At 1000 yards, EVERYTHING matters.
Lane
Northridge
Gold $$ Contributor
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