Thread: What happened here?

Hey there,

Was testing some ammo yesterday.

All loaded with 26gr CFE 223
All using Remington 7 1/2 primers
All once fired 5.56 Brass
Cleaned, swagged and pampered.


Image:
Left 10 PMC Brass/ADI 62gr FMJ
Next 10 RG Brass/ADI 62gr FMJ

Other three rows
10 PMC Brass/64gr Nosler BSB
10 FNB Brass/64gr Nosler BSB
10 RG Brass/64gr Nosler BSB

Issue:
If you look at the row of RG/ADI 62gr FMJ those bottom 6 misfired/failure to fire... See the weird dent in the primer? Ever seen that before? And any ideas on what caused it//dud primers?
Checked the cases, powder present.

RG cases are from the same batch as the Nosler BSB's fired and all 2010 year so not old..all cleaned properly and swagged.

Cheers guys, observations appreciated.

Greenie

Primer pockets too deep, causing primers not to be seated properly to ignite? I suspect they look weird because there was no pressure to seat them back as they didn't go bang.

That and you used something with Remington on the box - almost guaranteed to be rubbish

Or conversely the cases have been oversized, and the extractor isn't gripping the case tight enough to give enough firing pin strike to go bang (I.e. You've given yourself a headspace issue).

Cases over FL sized (sloppy) usually result in flat primers which is usually mistaken for a pressure issue. Primers not seated deep enough (as per 7x64) will cause misfires although generally reloaders tend to seat them too deep ie crush them. I cut my pockets to 120.5 thou and then preload the primers by 1 thou. You can roughly check the pocket depths with a vernier although I use a depth mic. Different brands of primers are also different in their thickness/depth so some will seat further onto the pockets. Firing pin protrusion can cause an issue as well although unlikely if you haven't had the problem the past.

not sure what you meant by swagged? Did you just neck size or full length resize?

All brass was full length resized and checked with Wilson case gauge.

What I find weird is it was only a few of the RG that failed?

Originally Posted by zimmer

not sure what you meant by swagged? Did you just neck size or full length resize?

Dillon swagger 600

Swager! spell checker

are the primers still live? pull the projectiles and heat one to check. Also are the shoulders set forward so the cases dont headspace properly

Also forgot to mention...

Rifle is a Colt LE6920 M4 Carbine
Approx 750 rounds down the spout.

Originally Posted by Marty Henry

are the primers still live? pull the projectiles and heat one to check. Also are the shoulders set forward so the cases dont headspace properly

Really? What with? I blow torch or light etc?

Originally Posted by 7x64

and you used something with Remington on the box - almost guaranteed to be rubbish

I have heard their ammo is questionable, but I have read that their 7 1/2 primers are the bees knees

Most Accurate Rifle Primers for Precision Reloading - PrecisionRifleBlog.com

and

https://www.blogger.com/blogin.g?blo...mer-study.html

But for some reason the sencond one which was awesome is now privet

Rem 7 1/2 Benchrest primers are excellent. On a par with CCI BR in my 223 for accuracy and low ES. Fed GM (SR Match) are not as good as the REM or CCI.

The only feature with the 7 1/2s is they are quite "fat" compared to say Fed SR Match.
So if primer pockets are shallow the Rems could end up sitting proud, or end up getting crushed by over zealous handloaders.
Essentially primers and primer pockets should align with SAAMI specs. So if you have a primer pocket that is shallow end of the spec and a primer that is at the fatter end of the spec there may be potential for proud primers.

Originally Posted by zimmer

Rem 7 1/2 Benchrest primers are excellent. On a par with CCI BR in my 223 for accuracy and low ES. Fed GM (SR Match) are not as good as the REM or CCI.

The only feature with the 7 1/2s is they are quite "fat" compared to say Fed SR Match.
So if primer pockets are shallow the Rems could end up sitting proud, or end up getting crushed by over zealous handloaders.
Essentially primers and primer pockets should align with SAAMI specs. So if you have a primer pocket that is shallow end of the spec and a primer that is at the fatter end of the spec there may be potential for proud primers.

OK, so I'm not sure what I can do to alter the depth of the primer pocket, I really just swaged them with the Dillon 600 as they were Mil spec once fired and wasn't planning on doing it again?

I'm guessing it is probably me being over zealous with the primer seating then? Is the fix just to take it a bit easier? I have a Hornady LNL AP press.

I still don't get why it only affected those 6 rounds all in a row.

--------------

Other than that, what other primers do you recommend specifically for M4 shooting 64gr-77gr? I really liked the Rem 7 1/2 burn pattern it just appeard to be better than the rest.

Cheers


P.S worse case I can bin the friggin RG brass...one of the guys as ASRA said they were crap and to stay away from RG

Mmmm yes don't use the Radway Green brass but I wouldn't rush into a primer change just yet. Maybe someone else with AR reloading experience can comment on best primers. CCI #41 are specifically designed for AR 223 but don't even know if they are available here. Rem 7 1/2s have the thicker cups at 0.025" compared to some of the others @ 0.020" so are a "safe" primer.