Strange Mark on Primers

[kylethunder380]

Hey guys, I recently noticed a strange mark on the primers of my fired cases. This happened only with my 'hottest' 9mm load (around 145pf), but it did happen 100% of the time with that load. I've been using a lighter recoil spring (8lb) than the factory (11lb) for so long that I'd forgotten about it until this happened. The mark looks like a lollipop, where the normal/round primer mark is the 'sucker' and the weird mark is the 'handle'. I can't take a photo of it or else I would, but it is basically as I've described. I tried putting my old recoil spring in, and guess what? It went away, completely. So, now I don't use that load because I prefer my lighter loads and the feel of my lighter spring, but I am still curious as to what could have been making that mark. I can understand that the slide was moving faster than it should have been, but could early ejection cause the firing pin (or something else?) to actually 'drag' on the primer before the case exits? No one I've shown my cases to has ever seen this. My gun is a 9mm EAA/Tanfoglio, and the firing pin looks fine at the tip (no burrs or anything like that).

Thanks,

-Kyle

[SLM]

It's a "tail" caused by the firing pin. The pin is still hitting the primer while the barrel is dropping. There used to be lots of reports of them on the CZ boards in the EAA/Tanfoglio 10mm guns. The fix was a heavier firing pin spring to retract the pin faster and a bit off the tip of the pin.

With your 9mm gun, just stick to the factory weight recoil spring or go up a pound or two if you're going to run hot loads through it and you should be fine.

[calishootr]

+1 to the barrel actually unlocking 'early' whilst the firing pin is sticking thru the breechface, causing the pin to 'wipe' down the primer face while still extended