7mm flattening primers issue?

S

skidooracer_99

New member
i been trying out some loads for a new tikka in 7mm rem mag. i was using 140g nosler bt's, and federal 215 magnum primers in brand new fl sized and fully prepped winchester brass. with H-1000 i was getting totally flattened primers from starting to max loads. so i tried RL 22 and was getting the same flat primers from start to max loads. i checked with my headspace gauge and the difference between new fl brass and the once fired brass was .019 which seems very high to me but for a belted magnum case is that tolerable? this is my first belted caliber to reload for. I thought excessice headspace was my problem, so i neck sized 6 of those once fired cases and tried starting to max loads with H 1000 again and same looking primers!! i was soo stumped. what i luckily did do was deprime and reprime just one of the new fl sized cases with a cc1 250 magnum primer instead and filled with a starting load of h 1000. all other specs the same....and no flattened primer!! looks exactly the same as an unfired primer. whats up with this? this is a new one to me! has anyone else had problems with federal 215 primers?
 
i would try the regular LR primers. i dont use magnum in mine anymore. what charge are you using? i was running 64.5gr rl 22 with a 154 interlock.
 
Originally Posted By: Jack RobertsYou are pushing the shoulder back too far.

Jack

+100

Jack nailed it on the head, throw that brass in the garbage because it has stretched in front of the belt. Start over with 3.0g below book max loads with new brass.

I have shot 7 mags for many, many years. With the 140g bullets, Most of them will love a load of 65.5-66.5g of H4350 with a Std Rem + 1/2 primer, bullet touching the lands; velocity with this load will be in the 3250-3300 fps area and fantastic accuracy.
 
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Jack Roberts and Ackleyman---Sorry guys, I don't understand how case stretching is affecting his primers so that their flatted? Could you explain this better?

I could possibly see how pushing the shoulder back too far may decrease overall case capacity "a bit" and that this could cause a minor increase in case pressure, but I find it hard to believe that this could be done to the level to cause "all" his rounds to show flattened primers.
 
When you push the shoulder to far back the firing pin pushes the case forward in the chamber before firing, then when it goes off the primmer blows back out of the case before the case comes back to the bolt face. That will make it flatten the primmer and also give you a false pressure sign.
Chris
 
guys this is exactly why i am soo stumped. it sounded like an excessive headspace issue to me causing exactly what yotedog describes above. or my second guess was what bigdog2 describes. thats why i tried neck sizing a few of those once fired cases with just the neck sizing die to eliminate both of those issues and still had same flat primers. i experimented with one case that was still new never fired and fl sized like all the rest, and primed it with a cci mag primer instead and primer was perfect looking! so that eliminates the headspace or oversizing issue right there. so what could the issue have been, has anyone ever experienced this before? did i maybe get a bad lot of federal primers or are they generally softer than cci?
 
Thanks Yotedog65284--good explaination, I can see that happening and it fits with what the others say.

I'm not an expert on primers, but from what I've read here over the years, it wouldn't surprise me that the variations in primers might help solve the issue. I'm not a belted mag shooter, so I've not run into this issue.
 
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I think you have a primer issue, the belt on the case should keep the firing pin from pushing the case forward in the chamber. I think you are on the right track by changing the primers.
 
I have the flat primer issue with my Savage action. I quit worrying about it years ago, as it did not change with different loads. It flattens most primers pretty well no matter what the load. My Remington does not do it.
 


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