Got to thinking again 6BR vs 6ppc in slow powder

[82boy]

OK guys heres one for you. In a 6PPC when using a slower powder like H4895 great success has been reported by opening up the flash holes. This is a good combo, and has a few wins behind it. Why don't they use a magnum primer with the slower powder like the 6mm Br guys?

Now when shooting the 6mm Br, most times people load slower powders like Varget (Which is close in burn rate to H4895.) Why don't they open up the flash holes, like the PPC guys? Many have reported great success with 450 CCI magnum primers or the Remington 7 1/2 which my understanding is it is also a magnum primer, could this be to accommodate the small flash holes?

Am I missing something here?

 

[82boy]

Wow, I am kind of surprised, 49 views and no answer.
Maybe I need to rephrase the question.

What is the theory of opening up the flash holes on a PPC when using H4895 powder, or what does this accomplish?
Why is not the same theory used on the BR cartridge? The two cartridges are similar in design, and close in case capacity.

 

[12man]

I am a Varminter who LOVEs Accurate guns, was always told NOT to open up the flash holeson the PPC's. The same thing with the 6BR, I have had good luck with H4895, 30 gr H4895 Rem 7 1/2 with Berger or Fowler 80 gr Bullets in the 6 BR.

 

[wapiti25]

Try some cases with both flash hole sizes. Year's ago I used 5 25-06 cases with 120gr bullet's using H870 powder which was too slow to get the pressure up to max. I marked each case and fired it with the same powder charge and several primers over the chrono and recorded the velocity. The cases had been selected with the same flash holes and weights of the case. After the first round of testing I reamed the flash holes to a larger size and repeated the previous firings. The result was a more uniform velocity although I did gain a few ft/sec. it was not as much as I had hoped. A study or test is a lot of work and takes a lot of bullets but the bottom line is it requires a lot of shot's to be statisically significant. You can find out about your gun, bullet, primer, powder, case, but it may not be revelent if you change anything. Good luck

 

[Cheechako]

82boy

I think the simple answer to your question is that there is no solid evidence to support a conclusion that changing flash holes in either cartridge accomplishes miracles, or, as you said, "great success". I, and others, have played around with the concept and, while it was fun and interesting, the results were less than earth shaking.

Both the PPC and the BR do just fine without that kind of tinkering. But if you need proof, try it for yourself.

Ray

 

[camac]

I am not sure if this is slightly off track but I read in a few places that a couple of 6-6.5*47Lapua users were struggling with accuracy until they opened up the primer holes. Not sure how true it is.
I think for the 6BR and 6PPC the general consensus is the small flasholes work. It is a tried and proven formula. Even reading the main 6mmBR page some people have had negative results trying to uniform the flasholes rather less open them up much. I think the fact that there is not many responses probably reflects this. If there were posiitive things to see you would get responses. Also bad negatives would probably get responsses too. BUT "Why fix something that ain't broke". These two cartridges have proven to be some of the most accurate available in their current configuration.

 

[MarkS]

82boy,

You will have better SD and ES in velocities if you leave the flashholes as is.

Mark Schronce