Went to the range yesterday to see how the Federal premiums w/ 150gr Partitions would shoot in my 280.First shot went right where it was supposed to. Second shot felt good but was very high.Opened the bolt(I,m pretty sure it opened easily)I looked at the case and the primer was flattened. I grabbed the first case and it was flattened a little but not as much as the second.It was hot 100-103 degrees.Could the pressure be raised that much from the heat?I had a box of Federal Classics that seemed to be hot also(flat primers no extraction problems). Are Federal shells loaded that hot? I am just paranoid that it could be a headspace problem? Thanks.

Heat raises pressures. Flattened primers are not indicative of headspace. The type of pressure that would effect headspace would be immediately known. Your bolt, if it didn't come apart, would more than likely not open without mechanical help. You would know something was wrong.

As far as the primers go, look closely at the edge of your primers to see if there is any roundness present. The flat primers you want to worry about are those where the edge is square and usually, but not always, is accompanied by a sticky bolt. Without the benefit of seeing your primers, I would venture a guess that if the edge of your primers are still rounded and the bolt opened easily, then you are probably okay.

Sometime you may run across a hotter than normal factory round. This doesn't mean that the whole box or brand should be suspect unless you are experiencing difficulty in opening your bolt with every round fired, in which case you should immediately cease shooting and seek professional help.

Anytime you are concerned about the headspace of your weapon or excess pressures, simply take your weapon and ammo to your gunsmith and have it checked.

Good luck,

Malm

Did you, by chance, leave the ammo in direct Sun light while shoting. The catridges could get quite hot this way and raise the presssure. Could explain diference in 1 first and 2 second shot.

Just a thought.

Pistolero
My experience has been, the exotic is seldom the causitive agent, the heat, sunlight. With that in mind how do you clean the barrel of the rifle? If there is a build up of jacket fouling in the barrel that too can cause pressures to build.
Jim

Welcome to Federal Land!

Allthough your concern is apt and there may be some other factor at work, flattened primers on federal factory are the rule as far as I can see.

Based on a number of different friends rifles in 6.5x55, 243 and 6mm rem, most primers are as flat as a pancake and so sharp at the edge you could cut with them. This in the UK where the last week apart, rain is the norm.

You should be able to fire factory ammo stored in the shade in a factory chamber at the temperatures you describe without danger.

Appreciate all the replys! The shells were in the direct sunlight. I'll hit the range at daybreak and see how they do. If it is a headspace problem would it do it with all ammo?I looked at some Rem brass I shot in the past and it appears fine.Thanks again!

Stonecreek,

Thank you for your reply and for giving me the chance to restate it. What I mean to say is: "The presence of a flat appearing primer does not "indicate" the presence of excess headspace". Meaning that one cannot pinpoint the presence of excessive headspace merely by the appearance of a flat looking primer.

For instance, sitting here next to me is 30 fired factory "Federal" brass, which was fired in a weapon with .012 excess headspace.

Now at first glance the primers appear flattened, but on closer examination by a trained eye and caliper, it is evident that "all" 30 factory primers were protruding .003-.005 yet the edges of the primers were still rounded though slightly.

One might conclude that the presence of the protruding primers would indicate "low pressure" loads. True, low pressure loads can and do result in protruding primers, which is also seen in those old sloppy 30-30's with excess headspace, but that alone does not make it so. So it would be wrong then to say that the presence of protruding primers is indicative of low pressure loads.

This is what I'm saying. Just because the primers appear flat, that doesn't indicate headspace trouble. I should have probably rephrased it to read: "flattened primers are not "always" indicative of headspace problems."

Of course experience shows us that sticky bolts, flat and protruding primers, case head separation, cratered primers etc, are not always the result of what we think or suspect.

That is why I ended the post by saying: "Anytime you are concerned about the headspace of your weapon or excess pressures, simply take your weapon and ammo to your gunsmith and have it checked."

After all is said and done, without being able to actually put an eyeball on the object in question, we are all just guessing...

Regards,

Malm

Malm:

Well put, an excellent clarification and useful information.