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Discussion Starter · #1 ·
Well a couple weeks ago I took my witness 10mm to the range to sight it in after replacing the factory front sight with a fiber dot sight. I looked at the brass the other day and found a curious phenominon on the primers. There were nice firing pin strikes but it looked as if the brass was being ejected while the firing pin was still out because the indents have a scrape that makes the firing pin marks look like a tear drop. I test fired some hand loads that are a little hotter than factory loads and some factory loads while at the range and with the hotter loads the issue is more pronounced than with the factory loads. OK here is my question, is this a timming issue? I replaced the factory spring for a more stout one but not the firing pin spring. Should I dig out the firing pin spring that came with the new recoil spring and replace the factory firing pin spring as well to solve this issue?
 

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It's called a firing pin drag mark. You're almost right on your guess-timate of how it happens. The leading cause is when the barrel unlocks (drops) from the shroud during recoil. The movement is more pronounced on shorter barrel guns as LeverAddict pointed out.

It doesn't hurt much of anything. You can alleviate it by a stronger firing pin RETURN spring (if you have one) or a harder brand of primer. A lighter striker or hammer spring also might help reduce it.

Hotter/faster/heavier loads tend to show it more, as you found out. :)
 

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Discussion Starter · #4 ·
Leveraddict
No the first range session when the gun was brand new did not show this type of primer strike. Also, I have the 5 inch match model so my witness is not a short barrel model. 8) 8)
Thren68
I will try installing the firing pin return spring that came with the new recoil spring to see if it reduces the issue, but since it does not hurt anything I won't worrie about it if, it is not completely eliminated. ;D ;D ;D
Thank you gentlemen for the information it is a great help. ;D ;D ;D
 

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mushernut said:
I will try installing the firing pin return spring that came with the new recoil spring to see if it reduces the issue, but since it does not hurt anything ......
Didn't say it doesn't hurt ANYTHING, just not by much. It will add more wear and tear to the firing pin as MountainWilliam pointed out. How much is determined by the firing pin design, construction, and firing pin channel. Correct it if you can, ignore it if you can't. An extra firing pin rolling around the bottom of your cleaning box isn't a bad thing when you have a 10mm. :)
 

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I've experienced the odd primer smears (known as "Wipe Marks") in a couple of guns, most notably a Bersa 45 Compact, and my oft-abused 40 Witness. The 40 didn't show any other signs that alarmed me, but the 45 did........it had a pretty strong firing pin spring in it, which caused the pin to rebound after it left the wipe mark. See the little dimples on the brass outside the primer area? The pin was banging back onto the brass before it was extracted, and leaving a dent. The gunsmith who was on BersaTalk at the time said it wasn't a problem, and to keep shooting the gun, they didn't have a history of the guns breaking firing pins, so he said not to worry about it. The gun did it with most factory-level loads, as does my Witness 40. The Witness has well over 40K rounds through it, and the firing pin is still original, so I don't let it bother me. The only thing that has broken was the extractor, and that was a ten minute fix, once I had the new one.



I decided that since (at that time) I didn't have a lot of 45ACP brass, it was a handy way of determining how many times the brass had been fired in that gun, which was the only 45 I owned. Every dimple meant one trip through the Bersa.

I've since added 5 more 45ACP guns...........no wait, make that six. Apparently I like them!

So much for my system. ::)

As for adding wear to the firing pin............I don't see any evidence of it. I took this picture after 2000 factory-level loads had gone through the Bersa, and it looks fine to me.



A firing pin with a squared-off edge (as in a Glop) might be a different matter. :p
 

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papajohn said:
I've experienced the odd primer smears (known as "Wipe Marks") in a couple of guns....
Ok. I'm finally going to do it. Gonna disagree with PapaJohn. ;)

They are firing pin drag marks, not "Wipe Marks".

http://firearmsid.com/A_CCIDStria.htm
http://projects.nfstc.org/firearms/module09/fir_m09_t05_01.htm

We now return you to your regular program.

My 40 has been making them in Winnie primers for years and tens of thousands of rounds. Still on the original firing pin with minimal or no wear as in PJ's. Try to fix it or ignore it as you wish. Shouldn't make much difference in the long run.
 

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Discussion Starter · #9 ·
Well, I replaced the firing pin spring and hope that will solve the issue but if it does not then I will just happily shoot my witness and see what happens. ;D ;D ;D ;D ;D ;D ;D ;D ;D
 

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Thren68 said:
Ok. I'm finally going to do it. Gonna disagree with PapaJohn. ;)
They are firing pin drag marks, not "Wipe Marks".
Hey, call them what you want, I didn't make it up. But if you think about it, they kinda look like.........ah, never mind. Family forum, and all that.

Besides, disagreeing with me isn't so unusual, for some folks it's a daily ritual. Asks my exes. ::)
 

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papajohn said:
Hey, call them what you want, I didn't make it up. But if you think about it, they kinda look like.........ah, never mind. Family forum, and all that.

Besides, disagreeing with me isn't so unusual, for some folks it's a daily ritual. Asks my exes. ::)
Kinda look like what? WHAT? What are you looking at that no one else here is? ;D

Jon
 

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planeflyer21 said:
Kinda look like what? WHAT? What are you looking at that no one else here is? ;D

Jon
He's been staring at that picture of Her on his wall too long. ;D
 

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Charlie98 said:
He's been staring at that picture of Her on his wall too long. ;D
We should lighten up.

Seriously, if PJs been eating at a fast-food place where his sombrero would double as a uniform, he's probably all too familiar with "wipe marks".

Jon
 
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