Flat Primer Help!!

[ant12hony]

Today I was shooting some of my reloads for a 7mm Rem Mag and with 58.1gr of IMR 4350 it was flattening primers but I couldn't see any other pressure signs. I was using Fed 215 Magnum primers and the were very flat! Please help.

Thanks a bunch;
Anthony

[fps plus]

Simple back off a grain or 2

[icehunter]

Back off as suggested above. Also I have always had pressure signs when using imr 4350. Fed 215 primers are more gooder,better ( good grammer eh!!) for the big WBY cases like 378 and 460. If it was me I would try some good ol H4831 ( not short cut) with cci mag primers. Just my .02 worth..

[FishHunterPro]

Originally Posted by ant12hony

Today I was shooting some of my reloads for a 7mm Rem Mag and with 58.1gr of IMR 4350 it was flattening primers but I couldn't see any other pressure signs. I was using Fed 215 Magnum primers and the were very flat! Please help.

Thanks a bunch;
Anthony

What's the bullet weight?

[bigjohncdn]

Yeah, back off a tad. But Fed are known for having the softer primer cups.

[ant12hony]

I am useing 140gr ballistic tips. Will I get any good groups if I back of or how does that work.

[shunda2]

Check the case length, often. MY 7 mag stretched cases quickly, I got a good slap and the primers were flattened. Using imr 4350

[ant12hony]

Thes were never fired cases and also 58.1 gr of IMR4350 is the start on 3 books so thats why I didnt know if I could believe the primer. There is also know other pressure signs. Just doing a bit of looking online and there was something about head space could anybody explain how this could have anything to do with it??

Thanks Anthony

[Salavee]

Originally Posted by icehunter

Back off as suggested above. Also I have always had pressure signs when using imr 4350. Fed 215 primers are more gooder,better ( good grammer eh!!) for the big WBY cases like 378 and 460. If it was me I would try some good ol H4831 ( not short cut) with cci mag primers. Just my .02 worth..

X2

[fps plus]

Check scale
Check seating depth
Are all brass same brand
Check barrel fouling
Check case length
Maybe a fast lot of powder
Maybe soft batch primers
Maybe tight bore

If load is listed for std primers and use a magnum one should reduce powder charge slightly

Check all and reduce charge

[elkhunter11]

I would be very surprised if a factory7mm remmag rifle is producing excessive pressure with 58.1gr of IMR 4350 behind a 140gr bullet, unless there is another issue. I am wondering why you would even bother going to .1 of a grain on a starting load.

[FishHunterPro]

Maybe it's because the load is to low?

[marxman]

how do you know they are too flat. some of my factory load primers are pretty flat. its easy to tell if you have a moderate pressure load but harder to tell whats going on by the primer in full pressure loads.if headspace is letting the primer pop out a bit before the pressure pushes the case back it wont help to reduce the load.

[Bergerboy]

Possible headspace issue?

[ant12hony]

Okay I'll check all those things.

Thanks For the help hopefully I can get it figured out!

Anthony

[qwert]

Originally Posted by ant12hony

Thes were never fired cases and also 58.1 gr of IMR4350 is the start on 3 books so thats why I didnt know if I could believe the primer. There is also know other pressure signs. Just doing a bit of looking online and there was something about head space could anybody explain how this could have anything to do with it??

Thanks Anthony

Did You use your case comparator to measure and record the head to datum length of your unfired brass and again after firing?

IMHO, for best performance and case life, all brass that is not a tight fit in the chamber before firing should be fire-formed using the false shoulder, or boolit seated hard into the lands method.

IMHO, for best performance and case life all brass, and especially belted or rimed brass, should be sized for minimum head clearance by 'head-spacing' (wrong term, but common usage) using the shoulder (and not the belt or rim).

As others have noted, excessive head clearance will cause the primer to back out of the case head on pressure rise after firing, and soft primers will flatten as the (now over-stretched case wall &) case head is slammed back against the bolt face. (This is the reason I usually suggest that new reloaders learn die adjustment using used and not new brass.) IMHO, primer flattening is a poor indicator of pressure, particularly with soft primers in cases not properly fire-formed to the individual chamber.

I suggest you search here and Google for 'proper die adjustment', 'partial resizing', and 'fire-forming for minimum head clearance (or head-space)'.

Good Luck, YMMV.

[James 1]

Post a picture of your cases.

[260 Rem]

A better "check" for over pressure is to use a chronograph. Many of the pressure indicators we look at can have other "causes". It is not uncommon to see varying degrees of primer flatening, cratering..etc. The more experience you have, the more likely you are to read the signs correctly. Another objective indicator of over pressure is rapid growth of the web diameter --- and the rapid growth of primer pockets. Now, if you get a combination of stiff bolt lift with flat primers, you are probably on to something. But, stiff bolt lift by itself, can be caused by other factors as well.

[Xbolt7mm]

Could you title your thread properly!

[ant12hony]

Originally Posted by Xbolt7mm

Could you title your thread properly!

Not everybody has a good emagination...

Sorry guys dont take pictures but they look like like the one on the right
I havent have time to look at any of those things yet... hopefully tomorrow

Thanks Anthony