What is so magical about SRP 7.62x39 brass?

[Twmaster]

Here lately I've seen some discussion about hand loading the 7.62x39 Russian case and mention of using a particular load and small rifle primers.

Some of the comments I saw seemed to be adamant that you use these small primer cases. FWIW I did not know there were small primer 7.62 cases. (turns out I have nearly 500 Rem SP cases in my stash)

I've been reloading for a a few years and am just not seeing what the big difference is other than primer size. (of course no mention of Magnum vs. standard primers was made).

So I'm scratching my head here. What's the deal?

Thanks.

 

[stubbicatt]

I am not familiar with these other threads you speak of. However, for a small capacity case using a relatively fast burning powder, a large rifle primer may provide too much "flash" for consistent pressures and therefore adversely affect accuracy.

In most "accuracy" applications in cases up to 308 or thereabouts, there are adherents to the "small rifle primer" school of thought, as it is believed that a more mild "spark" will result in better accuracy, and small primers can produce a smaller "spark."

The only other potential benefit I can think of is that some will say that cases with small rifle primers will contain higher pressures than the same case with a large rifle primer, all other things being equal, before the primer pocket "lets go." I don't know how much that bears on the 7.62x39, as it is not considered a high pressure cartridge.

--Thats all I've got.

 

[Ken70]

Goes back 40 years, 6PPC cartridge was based on the .220 Russian which had a small primer. That cartridge was based on 7.62x39 which normally is large primed. 6PPC has been the benchrest champion since it came out. Now there are other 6mm cartridges that are getting better. Google 6PPC and you can read about it. Interesting story...

 

[FROGO207]

Well if you had only small rifle primers these days and the brass had large holes this would not be the best situation.That would be my main reason to stock some small primer brass.