[Timothy]

Ran a box of new ammo and a hundred reloads through my new 10 mm Witness and was looking over the brass and noticed something new. Hope one of you can help explain it to me.
The firing pin dimple in the primer was “key hole” in shape. Under the magnifying glass I could see that there was a good round natural shaped dimple well centered and plenty deep....but extending outward from the center of the dimple there was a groove ½ the diameter of the firing pin in length and width decreasing in depth until it terminated at the surface of the primer. My first thought was that the firing pin was out of round or had a burr on it so I took the pin out and examined it. No problem with the pin! My next guess was that the pin might be skewed traveling forward and then centering itself as it came in contact with the primer. Told a friend about it and he said, “How do you know the groove is getting there before the dimple?” If the dimple happens first and then the groove takes place, it would indicate that the extraction process was taking place before the pin fully retracted. I didn’t think there was much chance of this happening but out of respect for his theory, I chambered a brass with only a primer (no powder, no bullet) in order that there would be no recoil and extraction. Guess what? Bang! No groove...just the normal dimple! As soon as I can get to the range I will index a couple rounds with a black marker at 12 o’clock and if the groove is at 9 o’clock, I guess he may be correct.
Has anyone else had this experience, and if so, what did you do to correct it?
Thanks in advance.

[stans]

This seems to be a common problem with Witness pistols, the firing pin just does not retract fast enough and the tip of the pin swipes the primer as the barrel unlocks. I have a TZ-75 Series 88, the precursor to the small frame Witness. I have tried heavy firing pin springs and recoil springs so heavy that the pistol would barely function. Although I was able to decrease the swiping, I never did totally eliminate the problem.

[coonan357]

sounds like a heavy firing pin , see if you can lighten one up , I would just carry an extra firing pin just in case , some of th rounds that the coonan shoot do that , its the real hot loads .I just deal with them .

[Jim Watson]

Saw the same make and model at a match yesterday. The shooter was sorting his brass from the other 10mm on the range by the skid mark. Heavy loads in Sig Sauers behave similarly. The barrel is dropping to unlock before the firing pin retracts, the skid mark is to 12 o'clock. Might be a good idea to keep a spare, but that is just the way the guns work.

[DonQatU]

Timothy, I wouldn't worry about it unless it causes functioning problems.

Just a bit of fire-pin drag.

Don

[winwun]

I am REALLY glad to see the input on this question. I have seen the same thing on pick-up stuff, and no one I asked had ANY idea.

[blades67]

My SIG Sauer pistols all do that with some of my warmer loads, my Kimber has also. I don't worry about it.