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Interesting data on primer compound weights

I was curious, so I measured. Regular calipers, cheap milligram scale, so the numbers are not precise, but the data still indicates well enough.

The rifle primers I measured, CCI250, Federal 215 Magnum Match, S&B Large Rifle Magnum, Winchester Large Rifle Magnum and White River Magnum Rifle, all have the same thickness primer cup.

The weight of the unfired primers are all within 0.15 grains of each other, except the White River Large Rifle magnum primer which is 0.38 grains heavier than the next heaviest S&B LRM. In order of lightest to heaviest - CCI250, Winchester Large Rifle Magnum, Federal 215 Magnum, S&B Large Rifle Magnum, , White River Large Rifle Magnum.

Federal 215 Magnum Match, Winchester Large Rifle magnum and S&B Large Rifle Magnum weigh within 0.04 grains of each other.

All the fired primer cups with anvils weighed exactly the same, 4.62 grains. Excluded is the White River LRM, I haven't used any yet, so I can't say if the cup and anvil weighs the same as the others. The thickness is the same, so the weight should also be the same.

I weighed 10 CCI35 primers average 19.59 grains, cups and anvils averaged 17.79 grains.

Large rifle primers have around 0.6 grains of primer compound, except the White River which may have roughly 50% more at 1.08 grains, to be confirmed once I use a few.

The CCI35 has around 1.8 grains of priming compound.

Again, not world class measuring tools, but the trend is clear.
 
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Interesting. I have tested the WRE LR primers side by side with CCI200s and BR2s and found a negligible difference in average velocities between them. Primer weight has more variables in play than one might think. The components are small (low mass) and how the tolerances mix can frustrate extracting any meaningfully consistent conclusions, especially when attempting to evaluate differences between brands (and types).
 
Interesting. I have tested the WRE LR primers side by side with CCI200s and BR2s and found a negligible difference in average velocities between them. Primer weight has more variables in play than one might think. The components are small (low mass) and how the tolerances mix can frustrate extracting any meaningfully consistent conclusions, especially when attempting to evaluate differences between brands (and types).

I do know that the Winchester LRM is the hottest primer of all these excluding the White River which I've not used yet, but the weight of it is so close to S&B and Federal, the primer compound composition is likely different as there is not appreciably more of it.

I explored this angle to try understand the powder equivalent of the primer compound, how many grains of powder is it energy equivalent to. Along the lines of "if you replace a regular primer with a magnum primer, how much less powder will give the same velocity", or vice versa. But this weighing just shows it needs to be tested by load and shoot.
 
What was it?

CW
 
I was curious, so I measured. Regular calipers, cheap milligram scale, so the numbers are not precise, but the data still indicates well enough.

The rifle primers I measured, CCI250, Federal 215 Magnum Match, S&B Large Rifle Magnum, Winchester Large Rifle Magnum and White River Magnum Rifle, all have the same thickness primer cup.

The weight of the unfired primers are all within 0.15 grains of each other, except the White River Large Rifle magnum primer which is 0.38 grains heavier than the next heaviest S&B LRM. In order of lightest to heaviest - CCI250, Winchester Large Rifle Magnum, Federal 215 Magnum, S&B Large Rifle Magnum, , White River Large Rifle Magnum.

Federal 215 Magnum Match, Winchester Large Rifle magnum and S&B Large Rifle Magnum weigh within 0.04 grains of each other.

All the fired primer cups with anvils weighed exactly the same, 4.62 grains. Excluded is the White River LRM, I haven't used any yet, so I can't say if the cup and anvil weighs the same as the others. The thickness is the same, so the weight should also be the same.

I weighed 10 CCI35 primers average 19.59 grains, cups and anvils averaged 17.79 grains.

Large rifle primers have around 0.6 grains of primer compound, except the White River which may have roughly 50% more at 1.08 grains, to be confirmed once I use a few.

The CCI35 has around 1.8 grains of priming compound.

Again, not world class measuring tools, but the trend is clear.
So, and are they all using the same compound, or do the heavier ones use different mixtures?
 
So, and are they all using the same compound, or do the heavier ones use different mixtures?
I have no idea as to the compound.

The mixtures must be different because the primer performance differs out of proportion to the weight difference of primer compound in the Winchester LRM.
 
I'm thinking it would work better to just test the difference in muzzle velocity to get a feel for the difference in effect the various primers have.
That said, I assume you'd be more interested in group size that MV per se.
 
So, and are they all using the same compound, or do the heavier ones use different mixtures?
These kinds of things are only shared at a generic level. The details are proprietary to each company.

The mixtures must be different because the primer performance differs out of proportion to the weight difference of primer compound in the Winchester LRM.
Yes, you are correct.

Primers carry a charge weight. Roughly speaking, a grain of primer compound is worth factors of the equal amount of propellent on a weight basis. So, variations in primer mix count for more than all that careful work we do to meter out our charges to the details.

The good news is, unless your primer batch was made when the good crew was out with the flu, you are probably not going to find many ugly ones. It does happen to all of them from time to time because humans are involved.

The threshold primer weight limit that affects a given individual is different. It is up to the individual to check their own issues and hope they don't own a sloppy batch. THE ONLY way to know this is to check you batch, and the only way to know how much Delta Mass is good or bad, is to test in your context.

I was privileged to get behind the curtains at several plants at several times in my career. Those details are considered private. If you had access to the bomb tests or primer test rigs, then you would understand. However, just because someone hasn't experienced a problem batch, doesn't mean those don't exist. YMMV
I'm thinking it would work better to just test the difference in muzzle velocity to get a feel for the difference in effect the various primers have.
That said, I assume you'd be more interested in group size that MV per se.
Yes, it is easy enough to collect the extreme "tails" (+6 sigma and -6 sigma) by weight sorting and go run your own testing. If you don't find a problem, it is because those are good primers, and the weight distributions are still small enough not to hurt you.

Just keep an eye on each batch and keep a diary. You don't have to weigh every one. Pull at least 30 at random and check the stats. If those look and test well, then you know for the next time.

If you stay in this game long enough, sooner or later you will get a batch that was done by the B-team. Even then, you can just sort them can keep rolling. YMMV
 
These kinds of things are only shared at a generic level. The details are proprietary to each company.


Yes, you are correct.

Primers carry a charge weight. Roughly speaking, a grain of primer compound is worth factors of the equal amount of propellent on a weight basis. So, variations in primer mix count for more than all that careful work we do to meter out our charges to the details.

The good news is, unless your primer batch was made when the good crew was out with the flu, you are probably not going to find many ugly ones. It does happen to all of them from time to time because humans are involved.

The threshold primer weight limit that affects a given individual is different. It is up to the individual to check their own issues and hope they don't own a sloppy batch. THE ONLY way to know this is to check you batch, and the only way to know how much Delta Mass is good or bad, is to test in your context.

I was privileged to get behind the curtains at several plants at several times in my career. Those details are considered private. If you had access to the bomb tests or primer test rigs, then you would understand. However, just because someone hasn't experienced a problem batch, doesn't mean those don't exist. YMMV

Yes, it is easy enough to collect the extreme "tails" (+6 sigma and -6 sigma) by weight sorting and go run your own testing. If you don't find a problem, it is because those are good primers, and the weight distributions are still small enough not to hurt you.

Just keep an eye on each batch and keep a diary. You don't have to weigh every one. Pull at least 30 at random and check the stats. If those look and test well, then you know for the next time.

If you stay in this game long enough, sooner or later you will get a batch that was done by the B-team. Even then, you can just sort them can keep rolling. YMMV
lol . . . yeah, I think I got some "B team" primers when I bought a brick of Remington 9 1/2's for the first time not long ago. I just can't get any consistency out of them. I probably should just give them away since now I'll never use them. On the other hand, my 7 1/2's have worked great for me. . .particularly since I've weight sorted them. :D
 
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lol . . . yeah, I think I got some "B team" primers when I bought a brick of Remington 9 1/2's for the first time not long ago. I just can't get any consistency out of them. I probably should just give them away since now I'll never use them. On the other hand, my 7 1/2's have worked great for me. . .particularly since I've weight sorted them. :D
I won't get sued when I tell you it has happened to all of them at some point, and some more often than others....
 

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