Weight sorting primers-Test

[Dave Way]

It's winter time, I'm bored and it's a great time to do tedious things before next shooting season. I have never weight sorted primers but have a few friends who do. When I asked them if it helped they said they weren't sure. The reason was they never knew if the variation was the priming mix or the metal cup and anvil. Tonight I did a little test to see what I could determine.

I weighed the primers left in a tray of Federal 205M's. 54 total.

1- 0.235 grams, 3.62gr
10- 0.236 grams, 3.64gr
27- 0.237 grams, 3.66gr
14- 0.238 grams, 3.68gr
2- 0.239 grams, 3.70gr

There did not seem to be much variation but I have never weighed primers before so I'm not sure. I picked one of the lightest, median and heaviest, color coded them and loaded them into sized 6.5x47L cases.



Next I fired them, de-primed the cases, pulled the anvils out of the cups and cleaned out the primer residue. I used CLR and a nylon brush but water and a nylon brush would have probably worked. I dried everything prior to re-weighing.



Then I went ahead and weighed everything again:

Primer, Original Weight, Fired Weight, Weight of Primer mix

----1----------0.235g---------0.214g------------0.021g--

----2----------0.237g---------0.215g------------0.022g--

----3----------0.239g---------0.215g------------0.024g--



While this was a very small sample and the results would need to be repeated with a larger test, the results did seem to show that at least in this case with these primers a heavier primer did mean the primer contained more priming compound. The cups and anvils were extremely uniform. All the anvils weighed 0.061g. One of the cups varied from the other two by 0.001g.

One final thing. The next time you blame a powder for being "Dirty" consider this, I fired three primers in a perfectly clean barrel. Here is the patch that came out! Dave.

 

[Puzzaz01]

This is going to be a very interesting thread to watch.

Darrin

 

[group therapy]

@group therapy

 

[Dusty Stevens]

Great job. I found that cups and anvils usually weighed the same as you did. They are stamped at the same time from the same sheet on the same dies so they should be close youd think. Primers also create their own pressure so weighing primers is a worthwhile effort at the top tier of long range benchrest. If you dont believe primers make their own pressure shoot a winchester and remington back to back in sorted fireformed cases and see the velocity difference. Good test sir thanks for sharing. You can clean your cups and anvils in an ultrasonic if you have one

 

[jepp2]

One final thing. The next time you blame a powder for being "Dirty" consider this, I fired three primers in a perfectly clean barrel. Here is the patch that came out! Dave.

Interesting study. I might have thought the weight variation would have been from the metallic components.

Before you blame the primers for being "Dirty", recognize that by firing them without having the added combustion products and back pressure from burning powder, I "think" most of the "Dirt" would have been consumed. But yet, just firing primers leaves a lot of residue.

 

[KevinThomas]

Great job. I found that cups and anvils usually weighed the same as you did. They are stamped at the same time from the same sheet on the same dies so they should be close youd think. Primers also create their own pressure so weighing primers is a worthwhile effort at the top tier of long range benchrest. If you dont believe primers make their own pressure shoot a winchester and remington back to back in sorted fireformed cases and see the velocity difference. Good test sir thanks for sharing. You can clean your cups and anvils in an ultrasonic if you have one

Well . . . sort of. If you ever get a chance to see primers made, yes, it’s the same strip of material, but there will be several punches nested together that will stamp out a number of anvils (same situation with cups, I might add) with every stroke of the press. All that I’ve seen collect all of them in a common bin beneath the press, and they aren’t kept separate by punch. Again, ditto for the cups. Just how much difference there is between those individual punches and dies I can’t say, but I’d have to imagine that given their size, it’s got to be minuscule. Priming compound is a bit of a different matter, and getting the correct amount in each cup is a matter of some precision. Interesting to not that in Lake City’s priming operation, the workers in that unit rotate around, doing a variety of different tasks within that operation. Except one; those who wipe the priming compound. That’s a very exacting job, and the slightest amount of difference in how it’s done results in primers containing various amounts off compound, with predictably poor results. Those individuals do that one job, almo#t exclusively, with their work stations set up EXACTLY for them, and them alone. Lots of little things like this go into making up the whole.

 

[dcali]

Well . . . sort of. If you ever get a chance to see primers made, yes, it’s the same strip of material, but there will be several punches nested together that will stamp out a number of anvils (same situation with cups, I might add) with every stroke of the press. All that I’ve seen collect all of them in a common bin beneath the press, and they aren’t kept separate by punch. Again, ditto for the cups. Just how much difference there is between those individual punches and dies I can’t say, but I’d have to imagine that given their size, it’s got to be minuscule. Priming compound is a bit of a different matter, and getting the correct amount in each cup is a matter of some precision. Interesting to not that in Lake City’s priming operation, the workers in that unit rotate around, doing a variety of different tasks within that operation. Except one; those who wipe the priming compound. That’s a very exacting job, and the slightest amount of difference in how it’s done results in primers containing various amounts off compound, with predictably poor results. Those individuals do that one job, almo#t exclusively, with their work stations set up EXACTLY for them, and them alone. Lots of little things like this go into making up the whole.

On a somewhat related note, the million dollar question is "what is the difference between match and regular primers?" As best I can tell, it's a few bucks a box. Am I wrong?

 

[Ledd Slinger]

Great test!
I've always wondered if the weight variation was actually the amount of priming compound or the anvil/cup. Excellent work!

I've always suspected it was the compound because you can literally see the variations in amount of compound just by looking at them.

 

[dskogman]

So there is a 16% weight difference in the priming compound. Sounds like a lot.
The $64,000,000 question is does it show up on the target?

 

[_Raining]

I thought someone else did something similar and posted to accurate shooter and it showed lower SD/ES for the small sample size.

http://forum.accurateshooter.com/th...d-is-acceptable-in-competition.3960990/page-7
Search for "All, the primer test is finished." and it will bring you to the results.

 

[KevinThomas]

On a somewhat related note, the million dollar question is "what is the difference between match and regular primers?" As best I can tell, it's a few bucks a box. Am I wrong?

And there’s probably a lot to that. I’ve heard from some employees at one manufacturer that there’s virtually no difference. On the other hand, CCIs cups are marked with a “B” for their Match (Benchrest) primers, while other makes appear identical in every regard. I’d assume there’s something there, rather than just a marketing ploy to dupe customers out of a few extra bucks. I think that’s one question that would have to be answered individually, maker by maker, to get a valid picture. I can tell you, the difference between LC’s normal (M43) and their Match primer (M34) used in the M118LRis considerable. Their normal primer, used in most everything else is essentially a Magnum primer, while the M34 is a much milder item. And as you’d expect, I’ve almost always seen better accuracy out of milder primers in 308/7.62 size cases than with Magnum versions. Time and a place for them, but the military tends two use them for everything, and generally for their purposes the trade off in accuracy isn’t an issue.

 

[Bart B.]

When Bob Jensen tested large rifle primers shooting BBs from 17 Rem cases through a chronograph, the RWS ones produced the smallest velocity spread. Lowest average, too. Evidence they're mild.

My favorite for longer ranges in 308 and 30 caliber magnum heavy bullet loads.

 

[Bart B.]

On a somewhat related note, the million dollar question is "what is the difference between match and regular primers?" As best I can tell, it's a few bucks a box. Am I wrong?

A Federal rep told me their 210M primers are made the same as regular 210 ones. Their difference is their flame output uniformity. Some batches get their mix more uniform as well as how uniform the wet slurry gets spread in the pellet cups to dry. He said the process was oft times called black magic.

He described the mixing process as much like mixing chocolate on a granite slab with straight edge paddles. Some people have the knack and techniques to do it better. This was back in the 1980's and I dont know if machines mix the slurry now.

Good technical info on primers, search for "a114616.pdf"

 

[Dusty Stevens]

When Bob Jensen tested large rifle primers shooting BBs from 17 Rem cases through a chronograph, the RWS ones produced the smallest velocity spread. Lowest average, too. Evidence they're mild.

My favorite for longer ranges in 308 and 30 caliber magnum heavy bullet loads.

How did he test large rifle primers in a 17rem?

 

[Bart B.]

How did he test large rifle primers in a 17rem?

Drill out then uniform the pocket first.

A BB gun barrel was threaded into the cut off chamber section of a shot out 17 Rem barrel.

 

[KevinThomas]

I recall the testing that Bob did, and as I recall he rigged up a short smoothbore, chronographing BBs to get the readings. I’m sure the Large primers were done in a similarly modified set-up. As I recall, there was also a series that tested the brisnce of various primers, by photographing the flash produced against a background of graph paper of some sort. In that instance I know that an action was modified to take a cut-off case, just ahead of the web. What the photos showed was essentially the raw flash produced by the primer, with minimal interference of case design and so on. It produced a very interesting series of photos, and there of was indeed some remarkable differences between the flashes produced by various types and brands. From clearly very violent and intense Magnum types, to some very mild flashes from some of the Benchrest or Target makes. Not at all difficult to see why primers can make such a pronounced, difference in a load when you saw these. I think the NRA printed up his results, but I have no idea what issues or in what other venues they may have published the results. I want to say he did all this testing in preparation for loading the ammo used in the 1992 Palma Championships fired that year in Raton, NM. He turned out some fine ammo, and while the Ruger rifles were a colossal flop, I don’t recall hearing a single negative word about the issued ammo.

 

[KevinThomas]

Sorry for the duplication Bart, your post appeared as I was typing!

 

[Ned Ludd]

On a somewhat related note, the million dollar question is "what is the difference between match and regular primers?" As best I can tell, it's a few bucks a box. Am I wrong?

According to Federal, the only potential difference is that senior and presumably more experienced individuals assemble the match primers on certain days using the exact same components that go into the non-match versions. In fact, that might not even be a difference if your primers were assembled by any of those individuals on a day they weren't making "match" primers.

Twp416's results are interesting, thanks very much for posting them. The priming compound looks to make up less than 10% of the total weight of an assembled primer. Although the primer total weights didn't differ by what I would consider a HUGE amount, nonetheless there was variance. The weight of the cups/anvils appeared to be very uniform in this sample set, not totally shocking for stamped metal parts. However, because the priming compound makes up less than 10% of the total unfired primer weight, that means the metal parts make up better than 90% of the total weight. In fact, the priming compound probably makes up even less of the total because the ash residue, which doesn't leave the cup or directly contribute toward combustion, was removed. So even small variance in the weight of the cup/anvil could potentially have a large impact on overall primer weight for the purpose of sorting.

The only suggestions I would make are that it would be preferable to use a balance capable of resolving to 0.1 mg. The milligram balance apparently worked ok for this part of the test, but ultimately, if velocity comparisons are also carried out using different weight primer sets, the extra digit might make a difference in the final values +/- SD. I have weighed a box of Fed205s and found only a 6 mg difference across all 100 primers (i.e. median +/- 3 mg). Finally, it would be interesting to weight the primers after firing, but before cleaning to determine on a weight basis how much (ash) residue actually remains in the primer and therefore does not contribute to powder ignition. The amount of priming compound that actually contributes to powder ignition may even be a much smaller fraction of the total primer weight.

I'll be very interested to see if you do anything more with this in terms of velocity testing. Thanks again for sharing your results!

 

[Bart B.]

I want to say he did all this testing in preparation for loading the ammo used in the 1992 Palma Championships fired that year in Raton, NM. He turned out some fine ammo, and while the Ruger rifles were a colossal flop, I don’t recall hearing a single negative word about the issued ammo.

I was one of a few Palma team guys that in 1991 worked up the load used for Sierra's first production lot of 155's. It was first shot in a 4 day match, 1 day at 600 and 1000 yards then 3 days across the Palma course. Several top shooters from around the world said it was the most accurate mass produced ammo they ever used.

Those Ruger rifles used barrels from Green Mountain. They were called wash tub rifles 'cause that's the size groups they shot at long range.

 

[KevinThomas]

Yep, I was involved with the development and some of the early testing of the 155s, and was on hand in Raton for the matches. Tough conditions, and I really got some appreciation for th Brits at that match. Definitely had their excrement consolidated!