Author Topic: Primer scratch (Read 589 times)

farmerboyMT · « **on:** November 05, 2004, 04:28:29 PM »

Just put the first 50 rounds through my new XD 40. I noticed on about 2/3 of the fired cases that the primer has a bit of a scratch leading away from the point of impact from the firing pin. It almost looks to me like maybe the firing pin is still out a tiny bit when the case is ejected. I'm really unfamiliar with handguns this is my first one so I didn't know if this was a common thing or not. The pistol behaved perfectly no jams, miss fires, or failure to feed. Shot really well too. If it makes any difference I was using American Eagle 155 gr FMJ. Any thoughts would be great.
Bryan Danley

Iowegan · « **Reply #1 on:** November 05, 2004, 04:55:35 PM »

I bought a new Ruger p-345 that does the same thing. The only thing I can figure is the firing pin must be staying forward while the slide is moving to the rear. So far it hasn't caused a problem but it makes you wonder???

Patriot_1776 · « **Reply #2 on:** November 05, 2004, 06:18:04 PM »

Yup, my Sig P220 and Baby Eagle 9mm do the same thing most of the time. It is nothing to worry about. In my opinion it shows that even the some of the more, or less, expensive pistols are the same way. Hence, that means it is definitely normal. Remember, a vast majority of the semi-autos today operate on a delayed-blowback principle. Meaning, the casing has not begun to be retracted until a certain amount of pressure is released out of the muzzle. During that decrease in pressure, the brass casing contracts slightly (after being stretched against the chamber's walls), and then proceeds the extraction. Even still, I believe the entire acton happens so darn fast (even the blink of an eye is a hair slower I think) that the firing pin does not have the time to retract back into it's housing. I see alot of brass lying around the range I know of that has been fired in a SA and some have the same thing. Maybe all of them do, but I won't waste my time finding out; there is just no reason to be concerned about it.

Patriot

Patriot_1776 · « **Reply #3 on:** November 06, 2004, 05:22:06 AM »

I need to make a slight correction. The delayed blowback principle is not the way I had explained. :oops:

The delayed blow back principle works like this: When the gun is fired, the barrel and the slide want to go back. But the bullet's friction inside the barrel, pushes the barrel forward, holding the slide etc in place. Once the bullet exits, the barrel moves back slightly releasing the catch on the slide, and then the slide can move back and extract the spent round. Sorry about the misinformation on my last post. Patriot

papajohn428 · « **Reply #4 on:** November 06, 2004, 08:59:34 AM »

Farmerboy, you did a good job of diagnosing the situation. Lots of semi-autos exhibit the same marks on fired ammo, the firing pin spring is not strong enough to retract the pin before the case is ejected, hence the "Wipe mark". I see the same thing in my EAA Witness 40 with hot loads, which increase the slide velocity enough to make the difference in the timing. It's never caused any problems, and the gun is totally reliable, so I don't worry about it. Enjoy that new XD!

Papajohn

farmerboyMT · « **Reply #5 on:** November 06, 2004, 12:34:48 PM »

Whew!! I had to wait two months for the supplier to get the gun to my dealer I was really dreading having to send it away for repair. Thanks for all the help
Bryan Danley

myronman3 · « **Reply #6 on:** November 07, 2004, 01:16:52 AM »

i loaded some 45 rounds once that were a bit too hot. they left what you are describing. if your loads arent hot, i would have the gun checked by a gunsmith or contact the manufacturer and see what they tell you. in my mind i think what is happening is that the slide is slamming back so hard that the pin is coming forward again and causing the "scratch" on the primer. maybe you need a stronger spring.

Savage · « **Reply #7 on:** November 07, 2004, 06:05:20 AM »

Primer swipe is an ongoing event with my Witness 10mm. A Wolff 22# recoil spring and an increased power firing pin spring didn't solve the problem. I think the barrel lugs are not properly fitted to the slide. Not a major problem, just wish I could fix it!
Savage

New Hampshire · « **Reply #8 on:** November 07, 2004, 09:16:22 AM »

As I can remember all Sig "P series" pistols supposedly do it (my 220 does.) I believe the Sig Sauer explination was that this was normal. The firing pin stays forward temporarily. They claimed it reduced fouling in the firing pin hole. Its just what I read and Im cant say yes or no wether I believe it. But since there have been NO problems I dont fret much over it.
Brian M.