Misfire, need help troubleshooting

[DShortt]

You've got it all right but I'm thinking that I missed resizing this one due to the neck tension and neck measurement at .311 when all others are .309 after firing, or maybe I was distracted and didn't push it all the way into the resizing die. I'm going to be resizing some more cases soon and going to experiment with that possibility.

That's all well and good. But.

That would mean you had a bad primer on the one case you forgot to resize.

Or the one batch of powder was bad out of the whole container.

Consider those odds.

It's simply unfathomable that a primer would fire correctly and soot up the inside of the case and not set off the charge. It doesn't matter if the bullet was loose in the case because it wasn't sized. Ever heard of fireforming? You don't need a tight bullet to case fit to set off a powder charge.

So.

You either loaded a fired case with a spent primer, or you're presenting false observations. Meaning, the interior of that case is not sooty. Or there was no powder in it. Or there was water in the case and the powder was wet. Probably quite a bit.

Now. If you want to continue to refuse to accept that you made mistakes, then you go ahead.

 

[jwv2001]

The primer did ignite because if find the soot inside the case around the primer area and the whole inside of the case has soot on the sides. However I did measure the powder charge and it was the same as I had loaded and looked ok.
So you're saying the even though it ignited it was not hot enough to ignite the powder? It just blew soot?

Yes. It's happened to me before. The OP stated that every other cartridge fired no problems. I don't think that the primer threw a spark, but just sizzled for lack of a better description. I wouldn't look any further than a bad primer.