Weird primer dimples.

[Black Jaque Janaviac]

I have had similar results from reduced power hammer springs, with both CCI and Winchester small pistol primers. I was getting consistent ignition, but the firing pin dimples were as you picture, or in some cases completely filled in. Went to a heavier hammer spring, the problem went away.

I wonder if this might be it. I checked my gun's (it's a Kimber Micro 9 btw) firing pin channel last night and I don't see any gap around the firing pin. So that halo might not be cratering in the classic sense, as in the primer flowing into the firing pin hole.

If you look closely:
*you'll notice that there is no difference in the diameter of the dimples. So it doesn't appear that the dimples are being pushed back.
*the halos are raised ever so slightly above the plain of the primer, but the main surface of the halo is flattened. It appears as though the halo was pushed back into the breech face, not into the firing pin channel.
*all the primers have well-rounded shoulders and none of them exhibit imprinting of the breech face, except for that part of the halo.

I am convinced that 35Remington is correct. The 1 1/2 primers are made of a softer/thinner cup. I am guessing that when the pin strikes the cup and makes the dimple, the metal surrounding the dimple stretches even thinner. That thinned halo then gets pushed back against the breech face, not into the firing pin channel. The rest of the primer surrounding the halo does not exhibit any breech face imprinting.

I am using the wrong primers, for this application and I probably have room to increase some. However, my goal was to match the velocity of the factory Fiocchi 125 grain XTP ammo, and at 996 fps I have succeeded.

[35remington]

What is occurring would have to go on for awhile before any problems occur, as a small amount of plating may eventually accumulate in the firing pin channel. Flushing out the channel periodically may be all that is needed.

If this is a defensive carry piece, the clean out probably should be more frequent. Or just switch primers.

Whatever. Carry guns should be cleaned more frequently than range toys anyway no matter what ammo or primer you are using.

[charlie b]

I do not disagree that they are softer/thinner, just that I have not had any failures in many thousands of rounds over the years.

I also saw that factory was compared to reloads. If I were the op I would change primers/ load until the problem goes away.

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[Black Jaque Janaviac]

OK.

Here's a picture of the firing pin poking through the channel. I don't think there is enough gap around the firing pin to allow the primer to flow in and create such a halo. This is why I think the halo is cause by the cup metal getting stretched thin by the pin, then getting pushed back against the breechface. Again, note there are no markings of the breechface on the rest of the primer. I think I am well below max pressure.

pin channel by frozenfrizzen, on Flickr

[edp2k]

That pic shows your problem right there.

First off, when firing the FP never stick out as much as in your pic, which looks like 1/8".
The primer will stop it when .030" to .0.050" is sticking out.

The problem is, the tip of you FP is too rounded, and when the FP is only protruding .030" there is a large gap between the FP nose and the hole in the breach.
since only a small portion of the FP will be sticking out when the primer goes off, the effective diameter of the FP is a lot less then the main shank dia of the FP.

if you had a FP with a more square (i.e. less round) tip then your problem would go away.

[35remington]

However it occurs, maintenance on a carry piece will see that it is not a problem. For a range toy do whatever you want as it is more of a moot point.

Most all centerfire firing pins I have seen have a rounded point. Glocks notably excepted.

[tazman]

I have had issues with Remington 1 1/2 primers failing in 9mm as well. Pierced primers both at the firing pin and edge. This was a problem for one brick of them so I just used them in 38 Special.
The loads I was using them where they failed was a midrange load that works perfectly with other primers. Mine was definitely a component failure rather than a load failure.

[Black Jaque Janaviac]

Edp2k,

I understand what you mean, but I don't think that is the situation here. If you go back and look at the primer photos it looks like the diameter of the halos are much larger than the fp holes. I don't quite know how to demonstrate it photographically though. I'd have to remove the firing pin, and photograph it next to one of the halos. Unfortunately I tossed the brass in the tumbler, so it would be some work to find 'em again.