Primer pressure differences - a concern?

[BruinGuy]

I was in the reloading store at Oak Tree, and asked about which primers were considered harder than others because I want to reload 7.62x39 for SKS and AK rifles, and don't want to risk accidental discharge.

Rolf warned me to watch out what primer I used, because, he said, they can vary the pressure as much as 2600 psi. I've not seen any information in my manuals expressing this as a concern or something to be wary of; all I'd heard was that some are softer than others.

I am new to reloading, so I'm starting all of my loads at the minimum charge. I know to look for overpressure signs on the cartridges and primers. Is there anything else I should be doing to watch out for or account for the variances in primers?

[BenHa]

I am guessing he is trying to say that different primer have different ignition rate (not sure what thcorrect term is) so CCI primer won't be the same as tula etc. So if you were to switch primer your load would be different

[rsrocket1]

Rolf seems to be more in tuned with shotshell loading than with metallic loading. There is a huge difference between a 10,000 psi shotshell load (nice) and an 12,600 shotshell load (overpressure). The problem is a little less severe when comparing a 40,000 psi 7.62x39 round and a 42,600 psi round (SAAMI max is 45,000 psi).

The pressure differences between metallic primers is much less than the differences between shotshell primers (which can be as much as 2,000 psi with the right combination). I know of no case where the same type of metallic primer from different companies will change the pressure by 2,600 psi.

You will be better off with harder primers such as CCI and Wolf/Tula than you would be with a softer primer such as Federal.

Maybe you should ask Rolf which primers are hot, medium and cold?

[mark501w]

Any change in components you show go back to your starting load & work back up.

[LynnJr]

http://riflemansjournal.blogspot.com/2009/06/primers-large-rifle-primer-study.html

Click on the above link of the work done by German Salazar.Once there you can visit all of his primer articles.

[BruinGuy]

Thanks for the replies, everyone. I'm starting all of my loads at the manual's minimum charge (and cross referencing the Lyman, Lee, and Hornady manuals with the bullet manufacturer's website info) and plan to work up slowly from there.

For better or for worse, when primers were nowhere to be found I managed to score a box of Federal large rifle primers. I plan to use them for bolt-action rifles, though, and use the CCI's I've acquired since for the autoloaders. I asked Rolf if there were harder primers I should consider for the SKS and AK, which is how the discussion of pressure differences got started.

Glad to know I don't need to worry too much about the primers causing overpressure - at least in my initial loads.

[wtkaiser]

Just to muddy the waters, CCI also makes a mil-spec primer specifically for auto-loaders. I'm a lever man, myself, so it's not an issue, but they are supposedly harder in the cup than standard primers. Having said that, know also that I've never seen them!