Primer Batch Difference

[Barossa_222]

Hi guys. Just a bit of curiosity. Have people found changes in performance when changing between batches of primers?

[Brad Y]

Sometimes no, sometimes yes. A chronograph session and a few strings at 1000yds will tell you!

[DenisA]

Personally I haven't had a good load get worse when changing between different batch numbers of the same primer. Definitely have with powder and bullets.

I may have just been lucky so far..

[ecomeat]

Dont ask me how i know this, because i am trying to avoid having to admit to weighing and weight-sorting Primers
One ctn of Federal 210 GM's i checked on my AnD120i scales ranged from 56.5 grams to 63 grams.
Its fairly hard to believe that a 10% difference in the explosive material in a Primer wont make any difference to your ignition.
The next carton that i checked were all over 60 grams, so i didnt sort them yet.
I read somewhere where Mr Litz and others were stating that if you weight range primers to 1 gram, you will halve your SD.
I tried it at 1000 yard BR, and had a 7" something average for 3 x 5 shot groups with a skinnier Maddco barrel.
I also used sorted ones at 500 Mtr Fly in the same Rifle and have been "up there" with the big boys toys.It won Heavy Gun at 300 mtrs a few weeks ago......so something is going right occasionally.
Or else i was like Denis, and just got lucky

[williada]

Tony you did not get lucky. I would say that only your scales are good enough to prove the difference. However I would point out that the wall thickness of the primer and its anvil can vary and you ain't necessarily measuring the fuel load. People often change brands because of thicker wall thickness to take up enlarged pockets. Sometimes a looser primer pocket is blamed when the primer wall thickness or hardness can be a can be different between batches.

Of course you have to balance the efficiency of doing all these checks against the effectiveness. I don't worry with a positive tune, but a negative barrel would want to be used with the tightest extreme spreads of velocity. I would only be concerned at long range (1000 yards) with a nodal or a neutral tune if primers brisance varied a bit. Of course a ten shot primer test up short would settle that. I want someone to invent a talking powder scale. I can't bloody see. David.

[ecomeat]

David,
The day I catch myself weighing spent Primers, so I can calculate the "payload", I will check myself into a mental institution
There are quite a few AnD 120i Scales in Australia now, since Aaron made us aware of them via this forum. I think Cam McEwan might have already been wearing his set out quietly for years, and just keeping quiet about it
It is actually very quick, and very easy to accurately sort the primers into 1.0 gram lots

[williada]

Tony, I just couldn't resist mentioning it. But your scales are top notch and prove a point. For me its too time consuming and I do a sample batch test up short. But just maybe if I wanted to get into a team, just maybe .... David.

[Cameron Mc]

Tony. Seeing you have time to spare I will ask a favour too.
I will leave 10,000 primers with you to batch. You never know there could be a bad egg amongst them.
Your findings would be worthwhile I am sure. I know you get much pleasure helping fellow eager learners.
Cheers
See you today!

[ecomeat]

Alan,
Is there any chance that I could get a more risqué "Smilie" to use ?
I would like to use one that has a single middle finger sticking up from a fist

[aaronraad]

Thought about reloading primers for a while until I read Albert & Oelberg's 1944 book Primers for Small Arms Cartridges "How to Load Primers - Formula- Suggestions - Theory for Handloaders and Experimenters"...I'd just have to invest too much in perspex blast shields...

I was thinking that the 280AI and long cases might benefit from a primer with flashtube arrangement, similar to the ones shown here? - http://iaaforum.org/forum3/viewtopic.php?f=8&t=14754&start=0

Although using a 22LR blank would make a lot more reloading sense....or how to reinvent the 5.6x57mm RWS adapter cartridge for 22LR and 22MAG???? Struggling for an original idea!

[BATattack]

Tony, I just couldn't resist mentioning it. But your scales are top notch and prove a point. For me its too time consuming and I do a sample batch test up short. But just maybe if I wanted to get into a team, just maybe .... David.

David what results would you see at close range that would indicate a good or bad primer?

[williada]

Adam,

Below is a picture of .308W 155 Sierra groups shot a long time ago at 100 yards from a machine rest. Its the relative difference in this test that is important. Only the primers were changed for the test. I have posted it before.

With any testing, you have to compare against a standard. Taking this a bit further from the general machine rest test, I have a pet load and known group shape as determined by the type of tune I am seeking. I won't say much more than this at this point in time due to embargo. Try and do this testing in the evening when temperatures have settled but with sufficient light.

Depending on the type of tune, it will absorb most if not all of the primer variances which can be picked up in the standard deviation of velocity spreads of an accurate chronograph. This would be a good use of the accurate magneto type chronograph. Don't use that for harmonic testing though.

So generally speaking I am looking for a nice round group before I start load development and generally speaking at short range you will see the vertical fliers flick away from central clusters as depicted below which demonstrates incompatible variances in burning. As Tony revealed earlier, it is the extreme spread that is important, not so much higher and lower velocities of different batches which you can adjust subtly with charge, and neck tension. (Free flight is more aimed at adjusting peak pressures but that also depends on the powder density). Hence the reason for comparing against a proven load or records. David.

[Barry Davies]

Tony,
You keep referring to the primer weight in grams.
I weigh my primers because I have done the testing ( many years ago ) and there is a difference. However, Fed 210 primers weigh about 5.5 GRAINS ( .3 0r so grams )
The variation is generally 5.4 to 5.6 with the odd one going more or less.
I have found the cups to be very consistent with no more than .02 gns variation, so accurate weighing does give an accurate indication of the weight of priming compound.
If you do the testing over a good number of primers you will eventually determine the variation from top weight to bottom weight. Whether you consider the effort worth while is up to ones self.

[williada]

Barry has probably done more testing and has more insight than most, and I would be guided by his advice. David.

[Barry Davies]

Hi David, I accept the flattery

Further to my last post re primer weighing.
No doubt some consider it totally unnecessary--probably is when you have the perfect tune and can tolerate 25 to 35 f/s variation.
Never the less every 10 f/s reduction in ES is a bonus.
Ask yourself-- Why do I use BR quality primers? ( actually I don't ) But why do people use them? Well they are considered to be of better quality ( debatable ) or so the manufacturer says, and charges accordingly. My tests on BR quality primers indicate they are no better than standard quality in terms of weight variation, and I have never been able to prove they give me better results on the target-- so what's the point?
Generally primers are very consistent but there are odd ones, either heavy or light and these are the ones that will cost you, particularly at long range.
Rest assured a primer ( of the same make and batch ) that weighs 5.3 gns and one that weighs 5.7 ( and it does happen )
Will give a different result at long range. So why not eliminate them?