Factory loads too hot?

18 February 2005, 02:09

I've got a howa 1500 30-06 that flattens primers with federal factory premium ammuntion. I couln't understand why this was happening so I made some mild reloads to compare. When I loaded them they were .015" longer than saami specs with the same bullet and guess what, they got stuck in the lands. I guess I found my problem. Has anyone else had this problem? Is this normal?

18 February 2005, 02:28

<9.3x62>

I've run into a similar issue with rounds where SAMMI and CIP spec throats seem to differ - like the 8x57. A standard American reamer can be short throated for some of the European ammo...

20 February 2005, 07:27

Bill Mc

Are you saying that the 30-06 chamber is short?

20 February 2005, 19:42

El Deguello

Flattened primers can be caused by a number of things, high pressure being merely one of these......

20 February 2005, 19:59

kraky

NEVERFLINCH-I'm confused about what you did. Are you saying you made an exact duplicate of the Federal load except for powder charge? And these got stuck in the lands?? Did the federal loads "stick in the lands"? If they did I would think you would have felt resistance closing the bolt or if you would try and eject a loaded round. If they felt fine I don't think they would have been in the lands bad enough to flatten primers. If I had to make a guess I would say that the factory brass was sized in a way the left some extra headspace. What happens is when the firing pin hits the primer it pushes the case ahead slightly. The powder ignites and the primer now backs out just slightly (a few .001") and hits the bolt face making it look like a high pressure flattening of the primer. This type of situation give the appearance of high pressure problems when there is no problem at all. If you have a friend with a headspace kit it would be interesting to take measurements off of the new federal rounds and compare them to the once fired brass that now is a "mirror" of your chamber dimensions.

21 February 2005, 01:53

Atkinson

Sounds like you didn't trim the cases and they are too long or your chamber is too short...It has to be one of the other.

21 February 2005, 22:57

Neverflinch

quote:
Originally posted by kraky:
NEVERFLINCH-I'm confused about what you did. Are you saying you made an exact duplicate of the Federal load except for powder charge? And these got stuck in the lands?? Did the federal loads "stick in the lands"?

Almost a duplicate, the reloads were .015" longer and got stuck the factory rounds did not. I was wondering if this short throat could cause enough of a pressure spike to flatten primers.

quote:
r ignites and the primer now backs out just slightly (a few .001") and hits the bolt face making it look like a high pressure flattening of the primer. This type of situation give the appearance of high pressure problems when there is no problem at all. If you have a friend with a headspace kit it would be interesting to take measurements off of the new federal rounds and compare them to the once fired brass that now is a "mirror" of your chamber dimensions.

I think you might be right here. I'll check the headspace, and see if there is a major difference.

21 February 2005, 23:07

Neverflinch

quote:
Originally posted by Atkinson:
Sounds like you didn't trim the cases and they are too long or your chamber is too short...It has to be one of the other.

The loads that flattened the primers were factory rounds. The reload cases were trimmed and deburred, and loaded to .015" longer than saami specs. They got stuck in the lands. So stuck, I had to push a cleaning rod down the muzzel and force it out. Never had a factory rifle set up so tight. Just wondering if any of you have ever come accross the same thing.

22 February 2005, 04:51

Bill Mc

When you measure the length, is it overall length or from the "ogive" of the bullet?

22 February 2005, 19:43

El Deguello

quote:
Almost a duplicate, the reloads were .015" longer and got stuck the factory rounds did not. I was wondering if this short throat could cause enough of a pressure spike to flatten primers.

Flattened primers can be caused by a number of things, high pressure being merely one of these......

22 February 2005, 20:49

Neverflinch

quote:
Originally posted by El Deguello:

Flattened primers can be caused by a number of things, high pressure being merely one of these......

YEA, I got that the first time.

22 February 2005, 20:51

Neverflinch

quote:
Originally posted by Bill Mc:
When you measure the length, is it overall length or from the "ogive" of the bullet?

No, it was just the COL. But I was using the exact same bullet as the factory loads. 165gr. sierra gameking spbt.

22 February 2005, 21:40

Stonecreek

Primers that give a flattened appearance in factory loads usually indicate that the headspace is somewhat generous. This doesn't mean that your rifle has "excessive" headspace. It just means that the factory loads are at minimum and your chamber is not. What happens is that the cartridge is shoved forward upon firing toward the front of the chamber. At the same time, the primer is backed out of the pocket slightly by the building pressure, until it contacts the bolt face. As the pressure continues to build, the case itself stretches and is shoved back against the bolt face, reseating the now slightly swelled primer. This causes the "flattened" appearance that is often mistaken as a sign of high pressure. Absent ridging around the firing pin imprint or other pressure "signs", this abundance of headspace with factory loads is the likely cause.

As to "dupicating" the factory loads with the "same" bullet, be aware that the bullets sold to the manufacturers often vary from those sold to handloaders. The "same" bullet may have a slightly different ogive, and factory bullets often have cannelures absent on reloader bullets. As a result, seating to the same length over all with the "same" bullet may or may not duplicate the relationship of the bullet bearing surface and the lands of the barrel.

23 February 2005, 06:56

Neverflinch

quote:
Originally posted by Stonecreek:
Primers that give a flattened appearance in factory loads usually indicate that the headspace is somewhat generous. This doesn't mean that your rifle has "excessive" headspace. It just means that the factory loads are at minimum and your chamber is not. What happens is that the cartridge is shoved forward upon firing toward the front of the chamber. At the same time, the primer is backed out of the pocket slightly by the building pressure, until it contacts the bolt face. As the pressure continues to build, the case itself stretches and is shoved back against the bolt face, reseating the now slightly swelled primer. This causes the "flattened" appearance that is often mistaken as a sign of high pressure. Absent ridging around the firing pin imprint or other pressure "signs", this abundance of headspace with factory loads is the likely cause.

As to "dupicating" the factory loads with the "same" bullet, be aware that the bullets sold to the manufacturers often vary from those sold to handloaders. The "same" bullet may have a slightly different ogive, and factory bullets often have cannelures absent on reloader bullets. As a result, seating to the same length over all with the "same" bullet may or may not duplicate the relationship of the bullet bearing surface and the lands of the barrel.

There are no ridges aroung the firing pin imprint so I assume this is the cause. I knew that sometimes bullets sold to manufacturers are sometimes different than box bullets but these seem to be the same. I guess in need to measure oal from the ogive and see. Thanks for your help.