I was out at the range a few days ago and I decided that I wanted to put a few rounds through my normal carry gun, a Rossi M677 with 2 inch barrel. I had just got a box of .357 mag Hornady critical defense ammo and figured that I wanted to know how it shot before I started depending on it in case of an emergency. As it turns out that was a good call on my part. The rounds hit just where they were supposed to, and recoil felt normal, but on the fourth round the cylinder bound up. It took me a few minutes to get the cylinder opened up to see what was going on. The primers had cratered, in one case badly enough that it prevented the cylinder from turning. I shot off the last two rounds in the gun, mostly because I didn’t believe what I was seeing. When I got home I checked some references, and many of them note that cratered primers can often be an indicator of pressure that is too high. Even Hornady’s own manual notes on page 69 that cratered primers are a possible sign of “loads becoming excessive”. What I wanted to ask was if anyone else had had this problem in the past? I included a picture of the case heads below and added an unfired round for comparison. For now I have gone back to carrying my handloads in this gun, but I’m not happy about it. If anyone knows what is going on with this ammo please let me know.

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True, they have craters but this could be from an oversize firing pin hole, too.

The primers don't look flattened at all. How easily did the cases extract?

They don't look overpressure at all, still nicely rounded on the edges. Was the revolver dirty under the extractor star?

cp1969—you’re right, the primers do not look flattened at all. The cases extracted easily. I don’t think that the firing pin hole is the problem, I just looked at it and it seems fine. Also I shot quite a bit of other ammo after I had the problem with the Hornady stuff and it all looked fine. The part that bothers me more than a possibility that the round could be over pressure is the fact that the cratering caused a malfunction in one of the most reliable firearms that I have ever owned. For high end defensive ammo one of my most important considerations is reliability, and this stuff failed that test as far as I am concerned.

Dragon88—I just went and checked. There is a light dusting of carbon under the extractor, but nothing that should have caused this.

I would pick-up a box of regular Hornady XTP ($20) and see if it happens with those rounds as well. Either way, you might want to give Hornady a call and discuss with them...

That's true. They'd probably be as interested in this problem as you are. I'm sure they've tested the snot out of these rounds, but nothing takes the place of actual field usage.

They might have gotten hold of a batch of really soft primers and would probably recall the whole lot if that was the case.

At any rate, they need to know about it.

Those primers don't indicate overpressure IMO. I've seen Winchester .357 Magnum factory ammo with severely flattened primers which are normal for that ammo even though they look very bad.

Like you I am concerned about the malfunction of your revolver. I would try to duplicate the problem after insuring there is nothing other than the ammo that might be causing the problem. If you do duplicate the problem I agree you should contact Hornady immediately.

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Thanks guys,
I have been half thinking that hornady may have deliberately used softer primers in order to guarantee ignition in a wide variety of firearms. If so I think that their design,or QC process is flawed. I have written to Hornady already, but they have not gotten in touch yet. I am heading back out to the range this evening, and I will try a few in my model 28 and see if the problem persists. Just so that this thread doesn’t sound like I’m bashing Hornady, I would like to say that I have used many of their products over the years, and this is the first serious problem that I have ever had