n5wmk wrote:Looking at your photos magnified, I see another little "divot" on each round, to the side of the main primer dimple. Wonder what's causing that? Is there something on the slide face causing that? Or is it a secondary bounce or something from the firing pin after the round fires? Would be interesting to see if that second little mark appears on one of the rounds that didn't fire with a single firing pin hit.
Also, some of the photos show the firing pin dimple pretty much in the center of the primer, on some of them there's a definite offset from center. Couple an off-center hit with a harder primer, and there might not be enough force for the primer cup to strike the internal anvil to ignite it.
That is quite common with almost any semi-auto handgun. It is firing pin "drag", caused by the case starting the ejection process before the firing pin has time to fully retract. Remember, the slide is moving backwards rather violently. Simple inertia will keep the firing pin forward for longer than it would if the slide was stationary.parabelum wrote:Yes, I noticed that some are off center and noted the presence of that tiny "divot". I am fairly new to Sig, so I did not think that is something too unusual. Hmm.
I wonder if this being a factory .40 Sig with a .357 barrel has anything to do with that? I noticed that the barrel in e2 upper appears a little loose, but it seems to be that way by design? Maybe the slight wiggle of the barrel during the cycling produces an off center strike?
I don't know.
In other words, it's perfectly normal.