Flat Primer Strikes?

[Hk-Itch]

Took my R9 out and shot it over the weekend and noticed that on some of the rounds (115 gn. GDHP) that the primer was flush, no indentation from the firing pin.  Just a small area where the pin had struck and fired the round but the surface was flat.  Also experienced some double feeds.  I put in an order for extra strength mag springs and am going to get some Mil-tec for lubing the gun.  But is there any concern for the flat primer strikes?

[Richard S]

HK:

I may have misunderstood, but if what you experienced were light strikes and it happens again, you might check to see if the firing pin assembly/channel has somehow become fouled.  I've seen it happen with other pocket pistols -- a combinaton of old lubricant, powder residue, and "pocket dreck" collecting there in an otherwise spotlessly clean gun.

Good luck!

[Hk-Itch]

Thanks for the info Richard.  I didn't see any light strikes to the primers.  What this is as best I can describe is that it looks as if where the firing pin strikes the primer and make an indentation to ignite the primer and powder, is totaly flat or filled in.  So instead of a spent cartridge with a dimple in the primer what I have (on some) is a totaly flat primer with a shiny little circle where the dimple would be.

[Richard S]

HK:

Hmmmmm . . . . I'm guessing now, but since it apparently occurred with only some of the rounds fired, it might have been due to a few hard primers. It doesn't sound like the firing pin is at fault.

[tequilamockingbird]

What you're describing, primer flattening, is associated with over pressure loads.

I've always suspected that there are other factors that may play into it, such as a run of primers that have a softer than normal metal forming the primer cup.

Primer flattening also can happen when a bullet gets shoved back in the case from being in a magazine and loaded (chambered) a couple times, but not fired.  The impact of hitting the feed ramp drives it back into the case.  The OAL is lessened, but more importantly it drive pressures up, sometimes dramatically.  I see a lot of people unload and load back up with their carry ammo when coming out of the range. They load the same round that came out of the chamber back in after a range session.  Not a good habit, IMO.  Myself, if a bullet has been chambered, it gets shot at the range (after being examined for set back or other damage), never loaded back in and carried.  Bullets are cheap, guns aren't.  

I wouldn't expect to see primer flattening from excess pressure with "normal" factory 9mm SAAMI spec rounds, but have definately seen it in +P+ and SMG handgun caliber ammo.  Were it me, I would definately check the ammo and make sure some LE stuff didn't find it's way into the Rohrbaugh, or maybe a "set back" round or 2 got fed through.

Hope this is of some help.

[Hk-Itch]

Thanks for the replies,  The ammo I've shot in the gun where Gold Dot 115gn. standard pressure.....at least thats what it says on the box and the head stamp.  But to tell you the truth when I touch off a round of this stuff, boy, does it seem hot!  I dunno maybe like you said, round set back from shooting.  The rounds are to new to have set back from loading and unloading.  And each of the rounds shot feel as though they have the same gusto.  Maybe a little judicious polishing of the feed ramp?

[tequilamockingbird]

I'd definately get a new box(s) of ammo, maybe from a different source / lot number if Speer GD.  Shoot the suspect stuff in a P7 or a Glock, which can handle whatever you put in the magazine all the way to +P+.  I'm wondering if Speer may have put the wrong stuff in the box, or just plain messed up and loaded too hot.  Or maybe (more likely) the box got dumped in the store, and someone put the wrong rounds back in it (I have seen this happen several times).  I'm just guessing here based on what I've seen happen at the range/shop. Feed ramp polishing will not have any impact on the situation if the ammo is out of specifications.

[Richard S]

Those are interesting and instructive comments, TM. I think you've diagnosed the problem. Thanks!

[Hk-Itch]

+1 to what Rich said and thanks.  Will try it out.

 Dave

[tequilamockingbird]

Thanks guys, I'm glad I could offer my help.  

[Richard S]

TW has written two must-read posts resulting from some recent discussions he had with Eric.  (The posts are headed "Eric Rohrbaugh Thoughts, Parts 1 & 2").  The second post contains a link to comments on ammunition from the Seecamp web site, the following paragraph of which supports some of TM's observations on the "flat-primer" question in this thread.

[size=10]Fired cases do not reliably reflect the force with which the primer was struck. Because one print is deeper than another doesn’t necessarily mean the deeper print was caused by a harder hit. (The depth of print in a fired case is not a true indicator of the force of the hit, since on explosion the primer usually mushrooms around the firing pin. In actuality, if there were no explosion, the print would almost always appear much shallower. It will be noted there are exceptions where the primer is flattened out against the breech face by the explosion or does not mushroom around the pin ~ giving the impression of a comparatively light hit. The uniformity of Hornady prints has impressed me because it indicates uniformity in primer quality and consistency of powder charges.) [/size]

It all reminds me once again that without the right ammunition even the most expensive handgun is little more effective than a rock in the hand.

[Hk-Itch]

Very nice Rich.....I appreciate the words from Eric R. on the very issue I was experiencing.

[Hk-Itch]

Ok, I don't know the significance.....but since I added the stronger mag springs I no longer can find any emptys with the flat primer strikes.....

[Reinz]

Howdy - I just experienced a similar situation yesterday myself HK.

But only with the Remington 115gr 100rd fun pac from WM.

The strikes look like they only scratched off the nickle plating of the primers, and there were no dents.  I only fired 6 rounds from this box.  Upon closer inspection with a 5x magnifying glass, 3 out of the 6 had a tiny dent, and 3 had just scratched off the plating.

These are not plus p.

They fired fine on the first strike.

This is the first time I have seen strikes like this.  As long as they work, I'm fine with it.


Reinz

[Hk-Itch]

Heard that Reinz, as long as they work!