Re: Flat primers, can I avoid it?

26 June 2004, 23:24

I have a 6.5-06 which has flattened the primers on every round that I've fired in it. I had the headspace checked and all is Ok there. My smith says not to worry about it since I've not experienced any other signs of high pressure.

Rick

26 June 2004, 20:49

Gatehouse

I'll ditto the headspace concerns...

I have a 375 H&H, that, when loaded with NEW brass, and light loads will SMOOSH the primer allover. By itself, I would think of high pressure.

But...When I resize the case, (partialy) and use max loads, there is no primer smooshing...

The rifle simply has a long throat and a big chamber...Not a bad thing for a dangerous game rifle.

I resize the case a little, leaving the neckonly sized about halfway, so it can still grip the bullet. After that, the primers look good..

27 June 2004, 00:48

<eldeguello>

Quote:

If your loads really are light, you probably have excessive headspace. If you eliminate headspace and still get flat primers, pressure is more than likely too high.

IF your loads are really light, like is often the case with cast-bullet loads, excessive headspace occurs when the primer blast (honest to gosh!!) pushes the case forward in the chamber, setting the shoulder back slightly, before the powder burns enough to increase pressure. The primer has backed out a little, and when the pressure gets high enough, it pushes the case back against the flattened primer, so that when you extract the case, the primer is back seated where it ought to be, and it appears as if the pressure was too high when it was too low!!

This is the reason why it is often recommended that once a case is used for a reduced or cast-bullet load, that it be reserved for that purpose only in future reloadings. In such a case, the rifle does not have excessive headspace, the reduced load creats such a condition when it is fired.

02 July 2004, 04:26

1894

Viht load data is pretty hot for modern cartridges such as the 308. What primers are you using?