Interesting data on primer compound weights

[big5ifty]

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.

 

[RegionRat]

I see @Mulligan has read your post and clicked a like on there.

For snickers and giggles, you could do a search on the word primer and his name. Better have the coffee pot on when you sit to read those threads...

 

[mikecr]

but the trend is clear.

What was it?

 

[JLT]

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).

 

[big5ifty]

What was it?

the trend was the difference between the weight of the cup and anvil compared to the weight of the unfired primer, per brand. not scientific, I know.

 

[big5ifty]

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.