45R
Member
This was from A Sig 220ST. The primer get a nice smack when the FP strikes it but what is the secondary hit? The breechface is smooth by the way. Thoughts.......
Help Funny looking primer strike
- Thread starter 45R
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45R
Member
The Sig has less that 200 rounds through it btw. So its still under the break in period but I find these casings odd.
P95Carry
Moderator Emeritus
I think for sure Fuff is on the right track. EVERY instance shows this 2º marking is off in the direction of the main FP indent .... and that odd artefact at its (indent) periphery.
So ... not much else could explain this it seems other than a slow pin recovery/retraction ... during initial barrel unlock.
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Just thought .... mark the cases of a coupla rounds (magic marker) and chamber them for single shot - with mark at 12 o'clock. Then fire each one, compare .. and relate the markings to their orientation in chamber.... if ya see what I mean.!
So ... not much else could explain this it seems other than a slow pin recovery/retraction ... during initial barrel unlock.
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Just thought .... mark the cases of a coupla rounds (magic marker) and chamber them for single shot - with mark at 12 o'clock. Then fire each one, compare .. and relate the markings to their orientation in chamber.... if ya see what I mean.!
Walosi
Member
I had a drag mark on the primers with my first 220. I posted the question on SIGForum, and received the reply that this is typical - the retraction of the firing pin is deliberately timed a bit slow to allow powder debris to blow by before it retracts.
This was echoed in later threads, by experienced 220 shooters as well as Chris Orndorf, a well known SIG armorer. Many, many rounds, and another 220 later, I still have the drag marks, and have had no bad results with the pins. Yours is a bit different, but appears to stem from the same timing.
A couple of the marks in your pics appear to be right on the edge of the primer pocket. Several of mine, in the first 200-300 rounnds, actually extended into the brass - just a nick on the edge of the pocket. After that, the drag mark shortened to a "teardrop" that remained constant.
This was echoed in later threads, by experienced 220 shooters as well as Chris Orndorf, a well known SIG armorer. Many, many rounds, and another 220 later, I still have the drag marks, and have had no bad results with the pins. Yours is a bit different, but appears to stem from the same timing.
A couple of the marks in your pics appear to be right on the edge of the primer pocket. Several of mine, in the first 200-300 rounnds, actually extended into the brass - just a nick on the edge of the pocket. After that, the drag mark shortened to a "teardrop" that remained constant.
BluesBear
member
Fuff nailed it as usual
Your firing pin isn't retracting. It's still protruding during ejection.
Your firing pin isn't retracting. It's still protruding during ejection.
blades67
Member
It could be a weak firing pin spring allowing the firing pin to bounce as the barrel is unlocking, or a recoil spring with too high a spring weight. Orient the drag mark to the 12 o'clock position (the barrel drops as it unlocks) and you can see how this may happen with a weak firing pin spring, or a recoil spring with too high a spring weight, creating enough momentum for the firing pin to bounce while the trigger is to the rear releasing the passive firing pin safety.
That's my S.W.A.G. anyway. My SIG Sauer P220 leaves the small drag mark but not the secondary firing pin strike.
That's my S.W.A.G. anyway. My SIG Sauer P220 leaves the small drag mark but not the secondary firing pin strike.
WvaBill
Member
Same indents on my 220ST. No problems with reliability so far. I thought it unusual, but probably a Sig thing.
Walosi
Member
WVABill - That is exactly what it is - a SIG thing. When a 1911 does this, it is time to replace the firing pn spring, and check the pin for damage. After years of packing and replacing parts on a 1911, the answer that the 220 was deliberately engineered that way was a shock - but that is just the way SIGs are 
45R
Member
Thanks guys. I was wondering what that was. The FP Channel was smooth when I pushed the FP forward during a field strip. An interesting concept.
You guys are the best!!!!
THR comes in once again!!
You guys are the best!!!!
THR comes in once again!!
FWIW, all three HK USP series pistols I have owned produce the precise same drag mark. It is simply, as mentioned above, a timing issue with the FP failing to retract before BBL unlock. It isn't just a SIG thing.
I don't have this on any of my 1911's using Wolff XP FP springs.
I don't have this on any of my 1911's using Wolff XP FP springs.
10-Ring
Member
Just out of curiosity, is this a 45 acp thing? Is it a subsonic round thing? Will it happen w/ other calibers...ie 40 S&W or 357 sig?
ksnecktieman
Member
Are you sure the secondary mark is on firing and not on chambering? If the firing pin is binding when the slide is in motion it might cause a slam fire? eject a round without firing, and inspect it. If you see a mark on it you have a safety problem. Two dimples on a primer spell danger to me.
WonderNine
member
Well, I've never seen any other auto guns leave marks like that...
That's a new one on me.
That's a new one on me.
Mike Irwin
Member
Many other guns do this as well.
My EAA Witness in 10mm often leaves the primer looking as if it has been struck by a piece of iron flat stock.
My EAA Witness in 10mm often leaves the primer looking as if it has been struck by a piece of iron flat stock.
45R
Member
I checked for burrs on the breechface and on the FPC before posting. The test you mentioned came up negative
Two Dimples on the spent casing was a red flag so I posted to figure out what the heck was going on. 
Master Blaster
Member
Glocks leave this drag mark because the firing pin is slow to retract.
But the second light hit on the edge of the primer is not a drag mark, it looks like a second disticnt hit. It looks like the pin is still out when the gun chambers the next round, can you say slam fire??? full auto?????
I would fire the gun with a mag with one extra round in it and when the second round chambers, stop and eject the round, if the round has a firing pin dent on the edge of the primer, you know that there is a problem. I would then return the gun along with the dented round and some spent casings to SIG, after calling for a warranty repair.
But the second light hit on the edge of the primer is not a drag mark, it looks like a second disticnt hit. It looks like the pin is still out when the gun chambers the next round, can you say slam fire??? full auto?????
I would fire the gun with a mag with one extra round in it and when the second round chambers, stop and eject the round, if the round has a firing pin dent on the edge of the primer, you know that there is a problem. I would then return the gun along with the dented round and some spent casings to SIG, after calling for a warranty repair.
wildehond
Member
Old Oil?
Hi
Have you cleaned the firing pin and firing return spring and reoiled them. I might be that the lubrication that was used for the storage of the gun has thickened. This might act as a damper on the recoilspring. That will slow it down conciderably.
wildehond
Hi
Have you cleaned the firing pin and firing return spring and reoiled them. I might be that the lubrication that was used for the storage of the gun has thickened. This might act as a damper on the recoilspring. That will slow it down conciderably.
wildehond
Brad Johnson
Member
Check and made sure that someone, somewhere, didn't accidently leave out the firing pin return spring (or possibly installed the incorrect spring). A missing or incorrect FP return spring will let the FP rebound under recoil, and could potentially cause marks like your pics show.
brad
brad
As most have said, the FP drag marks in the middle of the primer are fairly common and nothing to worry about. But, the obvious hit on the edge of the primer would worry me if it were my pistol. As Master Blaster said, those look like distinct and secondary FP hits as opposed to drag marks. The FP may be bouncing. That wouldn't cause a full auto or slam fire condition, but it isn't right.
pale horse
Member
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Get some brake cleaner and spray it into the fp hole, use a compressor to blow out all gunk and then add a small drop of oil to the fp and see if it changes.
45R
Member
Hey guys since the responses on THR have been 50/50 I took it upon myself to call Sig today.
1st Tech. Told him the condition of the gun (no marks on breech. FP channel smooth. No marks on chambered round. Only spent casing.)
Response:
1st Tech. Has it had any malfunctions.
45R: No I am worried about the 2nd dimple between the primer and the brass. I understand the drag mark is normal for Sigs but can this behavior cause a slam fire.
1st Tech. Its impossble for a Sig to Slam Fire.:banghead: He was pretty confident about this.
Went for second opinion
2nd SigTech. Told him about the dimples. Explained it with primary strike being Saturn and the 2nd strike an orbiting moon. He started that his 228 does that also. I stated that I have a picture posted and he looked it over. His response was that if everything is functional its not an issue. Also stated that its not impossible for a slam fire but if nothing is binding the FP in the channel I shouldnt have to worry about it. I asked him if he would be kind enough to send the picture to the Custom shop. He did that and will be calling me tomorrow or an email is waiting.
I'll update as I find more information.
Also I'll give the FP channel some solvent and get it blown out. Who knows it could be a strange break in process. If its worth anything the snapcap that is dedicated to the gun shows a distinct center punch primer strike. No secondary hits.
1st Tech. Told him the condition of the gun (no marks on breech. FP channel smooth. No marks on chambered round. Only spent casing.)
Response:
1st Tech. Has it had any malfunctions.
45R: No I am worried about the 2nd dimple between the primer and the brass. I understand the drag mark is normal for Sigs but can this behavior cause a slam fire.
1st Tech. Its impossble for a Sig to Slam Fire.:banghead: He was pretty confident about this.
Went for second opinion
2nd SigTech. Told him about the dimples. Explained it with primary strike being Saturn and the 2nd strike an orbiting moon. He started that his 228 does that also. I stated that I have a picture posted and he looked it over. His response was that if everything is functional its not an issue. Also stated that its not impossible for a slam fire but if nothing is binding the FP in the channel I shouldnt have to worry about it. I asked him if he would be kind enough to send the picture to the Custom shop. He did that and will be calling me tomorrow or an email is waiting.
I'll update as I find more information.
Also I'll give the FP channel some solvent and get it blown out. Who knows it could be a strange break in process. If its worth anything the snapcap that is dedicated to the gun shows a distinct center punch primer strike. No secondary hits.
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