What is causing firing pin drag mark?

What is causing firing pin drag mark?

What could be causing this "drag mark" of the firing pin?

The breech face has the step documented elsewhere on this forum. Is the funny firing pin indentation caused by that? Or is there some other problem, too?

Looks like premature unlocking. The barrel is trying to unlock - drop out of battery - while the firing pin is still extended past the breechface. The "tail" on the firing pin strike is from the tip of the pin being cammed back into the breechface as the barrel unlocks. It usually means that the gun is unlocking while chamber pressure is higher than it should be, and the ejector imprint and bent rim would seem to support that. Are you shooting really hot ammunition? Or, are you using really light springs?

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Are you shooting really hot ammunition? Or, are you using really light springs?

Factory ammo, Remington and Norinco. Brand new gun, only 300 shots fired. No modifications.

Is the gun a model with a firing pin obstruction?

If so, I'd take it apart and look for signs that the "timing" was off and the firing pin not free to retract normally. Dings, dents, and burrs on the firing pin or the obstructor are not good.

Oh yes, it's got a firing pin block. That could explain the firing pin dragging on the primer. But what explains the dent on the rim?

The gun is giving me grief in the accuracy department, too. 5"-6" groups at 25 yards, when I can shoot about 2" with my other guns.

Frame to slide has 0.012" vertical and 0.006" horizontal play at the rear.

Barrel is very generously fitted.

I am waiting for the shop gunsmith to evaluate the gun. The manufacturer has already instructed to send it back, but I am on another continent so there is heavy paperwork involved in shipping the gun.

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But what explains the dent on the rim?

Dents such as this can be caused by a matching protrusion on a poorly finished breechface. These are usually found adjacent to the left hand (as viewed from the rear) breech face guide block. Does the breechface step you reported in Post #1 match the dent in the rim?

What is the make and model of this gun?

You mention shooting 8 rounds. Are these from an 8 round magazine or a full 7 round magazine with a chambered cartridge. If with a 7 round magazine, how do load the 8th cartridge in the chamber?

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Dents such as this can be caused by a matching protrusion on a poorly finished breechface.

There is that ledge on this gun's breechface. I am not sure if the mark on the rim is from that or from the ejector. I do not have the gun anymore so I cannot check. The gun is going back to the factory.

>You mention shooting 8 rounds.

I use 8 round magazines. But these problems are not affected by the round count in the magazine. Every empty case has the same marks.

zebrazebrazebrazebra (Order a Wolff firing pin spring) zebrazebrazebrazebra

Hey Johnny, did you notice the bent rim on those cases?

Are all rounds getting the rim damage? It appears to me that there is a feeding problem that may not be showing up as such. Is the disconnector rail driving the rim forward before chambering? I've seen that damage before, but can't remember... But I'll bet we are striking the barrel ramp.

This damage appears to be so severe that I doubt it can happen during feeding. If it was the disconnector rail causing this damage, the front of the round should be wedged onto something solidly. Sasu hasn't complained about feeding problems, which I am sure he should have, if a round was wedged so solidly for the disconnector rail to cause this.

Somehow I believe it happens during firing, when the case is forced back by the expanding gases with authority. He mentions something about a step on the breech face. Could we see some pictures of this "step"?

I was thinking that there should be at least intermittent feeding problems also, if this was the case. I wish I could remember where I've seen this... Pics would be nice.

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Somehow I believe it happens during firing, when the case is forced back by the expanding gases with authority. He mentions something about a step on the breech face. Could we see some pictures of this "step"?

I have been perplexed by the amount of damage to a rim, which is the sturdiest part of a casing. I think that John may have nailed it down, as occurring during firing.

Without pics of the breech face, we may never know.

I've gotten to the point that I try to mark parts when we send a gun back to the factories for service. I've gone so far as to call and speak to the 'smith that corrected a problem. They all usually keep their lips glued shut as to the cause of the problem(s). They want you to take their training and become a warranty station. I don't want those complications.

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Hey Johnny, did you notice the bent rim on those cases?

Yessir. That's a breechface machining problem, unrelated to the firing pin marks...which are caused by a second strike of the pin.

Here's what happens:

The pin fires the primer and starts the powder. The pin retracts. The slide is slammed violently backward in recoil. The firing pin bounces off the firing pin stop and the spring... unable to control it... allows the pin to move forward and protrude from the port just as the case begins primary extraction and drops lower on the breechface.

If the firing pin stop falls just far enough to offer a solid backing for the pin... but not far enough to drop completely out of position... you get deep indents on the primer, such as the ones shown as the case smacks the ejector.

In extreme circumstances, the pin can ride forward with enough energy to strike the primer, but the hit isn't as deep as it is here... and normally not as far off-center. Many times, it goes completely unnoticed... like the tiny dents in rifle primers after chambering a round on a Garand or M14.

The slide strikes the impact abutment, and the stop returns to position, and the firing pin resets without offering any further clues that the event occurred.

Pistols with passive firing pin blocking systems such as the Series 80 utilize shorter, softer firing pin springs to insure more reliable ignition should something be a little "off" in the release timing of the pin. Couple that with loosely fitted firing pin stops, and you've got the recipe for the marks shown above. I had a neighbor with a new XSE Combat Commander that was doing the same thing... and it was occasionally dropping the firing pin stop low enough to catch the hammer and tie up the gun. A 2-dollar firing pin spring cured it.

I've always associated the tear-drop mark on the case with guns that use a firing pin safety, but I never considered that the f.p. might be striking twice! Definitely makes sense.

Most of the non-1911 guns with this feature have very heavy firing pins so I figured they retract slowly because of the mass and because their springs are weak by design. One company's ad crew has made this teardrop mark into a "safety feature" and will tell customers that the firing pin is designed to hang out that way to keep burned powder from clogging the f.p. hole. Not too wild about that story.

Early 1911 customization manuals suggest that the f.p. stop be drilled for a set screw to insure that the stop cannot drop out during firing. That was a "gotta have" modification at one time, but I think it was fixing the wrong part.

David, I've spoken with lots of those same guys you mentioned. The reality is that they haven't a clue what is wrong with the gun, either! Occasionally I've offered to sell them the fix for a common problem just to see what their reaction would be... usually it is: "we are not amused!"

Sorry, no more photos of the gun. The gun is on its way to the manufacturer for repairs.

The firing explanation by 1911Tuner sounds plausible. Still I feel sorry for the pin which is getting this sideways force applied to it when the case is being ejected.

I checked many other fired cases. All of them have the same extra pin mark, but it's size varies.

I will post a couple more images, where the relative position of the dented rim and the extra firing pin mark can be seen. As soon Photobucket is up and running again.

It's too bad that someone has to suffer with this trouble, but good for everyone else, as we get a lesson in what's happening, and how to address it!

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Yessir. That's a breechface machining problem, unrelated to the firing pin marks... which are caused by a second strike of the pin

I agree that there was probably a "step" machined into the breechface but I'll have to respectfully disagree with the latter. That teardrop shaped firing pin impression on pistol cases is usually caused by "firing pin drag," which occurs when the firing pin is still partially protruding past the breechface when the barrel unlocks. The barrel (and case) move downwards and "drag" the primer across the tip of the firing pin. It's pretty common with many different types of pistols.

Ammo (primer hardness) is also a factor. Sometimes I will test fire a pistol with several different brands of ammo and examine the cases under a microscope. Some brands will show the firing pin drag and some won't (or the drag mark will be much smaller) when fired from the same pistol under the same conditions.

The bounce that Tuner described is common in military rifles like M1s, M14s and M16s but I don't think it's the cause in this case.

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That teardrop shaped firing pin impression on pistol cases is usually caused by "firing pin drag," which occurs when the firing pin is still partially protruding past the breechface when the barrel unlocks.

Look at the first photo close, Dave. It may just be my eyes, but it doesn't look like a normal teardrop drag mark. It's a separate strike altogether. Different set of mechanics than those that cause the infamous .40 S&W "Tadpole Tail."

Interesting thread. My first Colt had a step in the breech face that left marks on the rim, but didn't bend it.

Been doing firearms forensics for a few years, I don't have expert status, but I agree with Dave about the first pic... it's FP drag.

It tends to fool a person as it appears the point of origin doesn't show to be the primer strike area. What I've seen before, is the FP has retracted enough not give the text book sign of drag, but it's still out far enough to catch the indent and make that type of mark. That will happen if the gun will hold lock up a touch longer than what you see in pics 2 & 3.

You'll notice that's it's wide where the point of initial contact is made, then tapers out to the 11:00 position. It will do that as the FP retracts.

Pic 2 & 3 looks tear drop to me, heading off in the 11:00 position, followed by scuff along the primer surface... that's text book FP drag there.

I would say it's definitely unlock/timing problem, but very minutely inconsistent, as it shows it doesn't do it hard and fast every time.

Yeehaa! Let the debate begin! Wichaka... Welcome!

Think about it like this:

When the round fires, the case rim is slammed backward into the breechface under high forces... where it remains for as long as the bullet is present and keeping pressure on it... as evidenced by the bent rim. The firing pin can't protrude through the port just yet. It's blocked.

The slide and barrel reach the start of the linkdown point. Here, there's no gap between barrel and slide, and even though the pressure is off the case, it's still pretty much in the same place in the chamber that it was under pressure... and still against the breechface, albeit not under force.

The barrel starts to tilt, beginning primary extraction. Now we have a growing gap between the case rim and the breechface. As the barrel heads for full linkdown, the case has started to drop as the extractor starts to yank it free of the chamber. Now, we have the location for the second strike...which is roughly the diameter of the pin, and that's just about where the mark is. The firing pin obeys Newton and stand still while the slide is literally yanked out from under it.

On to the drag mark. If the firing pin strikes a second time, and doesn't or can't immediately retract:

The firing pin... standing still while the slide moves rearward, bears against the primer as the barrel drops further, creating the drag mark that grows more shallow as the pin tries to retract. Lateral forces on the pin created by the falling case prevents its immediate retraction into the port... essentially friction-locking it in place.

Now... To the things I've noticed that led me to this theory. I keep check on my fired brass. Although I don't visually inspect each one after every range trip, I do look at a few every so often as I size and decap. Whenever I start to notice very tiny second strikes on the primers... about the same depth and size as the "Garand" primer marks...I know it's time to change firing pin springs, and the marks disappear.

So... The second strike and the tadpole tail are related, and caused by the same mechanics, but one... the second strike... is the first to occur. If unnoticed or ignored... it progresses to the tadpole tail drag mark.

Standin' by...

I'm following you on what you're saying, I really am.

Would like to see some of your cases that have the double FP strikes.

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"When the round fires, the case rim is slammed backward into the breechface under high forces... where it remains for as long as the bullet is present and keeping pressure on it... as evidenced by the bent rim. The firing pin can't protrude through the port just yet. It's blocked."

I lost you with the above. FP blocked by what?

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"Lateral forces on the pin created by the falling case prevents its immediate retraction into the port... essentially friction-locking it in place."

This doesn't make sense when coupled with your above statement.

There's not enough FP protruding into the primer to create the friction needed to lock it in place. If it does get locked into place, by the forces of the falling case... then you have FP drag.

So am I missing something, what's applying the lateral force?

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"about the same depth and size as the "Garand" primer marks"

What are you referring to as the "Garand" primer marks?

FP drag can also be caused by a weak FP spring, as it doesn't force the FP back fast enough after ignition.

I guess one would have to figure out how much spring pressure (lbs) it would take to over come the newton law of what you're thinking of here.

Like steel triggers, it would more likely happen with steel FP's than the type made of Ti.

My Kimber makes a similar mark on the rim and primer though not nearly as pronounced, definitely not bending the rim to any extent. It just makes a slight indentation in the same pattern as shown above. Just out of curiosity, if there are slight marks on the rim of the casing, is it safe to reload or would all of my saved spent brass be completely worthless?

Also I just noticed, the line indentation across the rim of the casing, just to the lower side of it, am I seeing a little rectangle? Would that be made by the ejector?

Your brass should be good to go for reloading.

Good eye, very good eye... yes, that does appear to be possibly the ejector mark.

No matter which mechanism caused the tear-drop mark on the primer, and IF I am correct in assuming that the tear is towards the upper part of the case (as it is in the chamber), then that deformation of the rim is towards the left side of the rim. So, there should be a huge step at that side of the breech face, if it was to cause so much deformation. I mean look at the depth of that ledge there, it should be close to 1 mm. What was the manufacturer of those pistols which had a step on their breech face? We were discussing that some time ago.

On the cases there is an indentation other then the one bending the rim. From bottom to top pic. On the last pic there is an indent at the beginning of the 4. In the middle pic, it's position lowers in relation to the bent rim, see the beginning of the R. And in the top pic there is only a very slight indentation. The casing in the top pic most likely is made of harder brass.

If SASU were to keep on shooting this pistol like it was before sending it back, would he eventually damage the nose of the firing pin?

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I lost you with the above. FP blocked by what?

By the case pressed hard against the breechface under pressure. Bare slide. remove the extractor to lessen resistance. Place a case into normal position and push it hard against the breechface. Will the firing pin protrude? No. Can't.

Looking at the next batch of photos in Post #25...The top one appears to be a second strike mark, while the others look like tadpole tail drag marks. Quote:
This doesn't make sense when coupled with your above statement.

It does if you think about the firing pin coming through the port after a gap is created by extraction of the case. It could be that the pin is against the primer during the whole process, and when the gap opens... just walks out.

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So am I missing something, what's applying the lateral force

If the firing pin is out of the port, and has made a small secondary dent in the primer as the barrel begins to drop... bringing the still unextracted case along with it... the pin is trapped by the lower wall of the port and the depth of the indentation in the primer.

Forced against the lower wall of the port by this vertical force... it can't retract.

To demonstrate... remove the firing pin spring and insert the pin so that it protrudes. Push down on the top of the pin. That's the mechanism at work.

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What are you referring to as the "Garand" primer marks?

M1 Garands and M-14 rifles have floating firing pins without springs. When the rifle feeds and goes to battery at full speed, the firing pin will mark the primer lightly.

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FP drag can also be cause by a weak FP spring, as it doesn't force the FP back fast enough after ignition.

Of course it can... but how does the firing pin get back through the port until after extraction has started and created a small gap for it to move into? The second strike and the tadpole tail mark are closely related.. .but they're not the same. The second strike is the drag mark in infancy... when the spring starts to weaken... and it usually goes unnoticed or ignored. Only when it becomes obvious does it get attention.

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Like steel triggers, it would more likely happen with steel FP's than the type made of Ti.

Yep. Just like a steel trigger... The heavier the firing pin/trigger, the more spring it needs to overcome its inertial reaction to sudden acceleration and deceleration.

Unfortunately, I don't have any of the second strike cases on hand. When I find'em, it's during the resize/decap operation... so they're long gone. I just go ahead and change out the FP springs on all the guns that did range duty that day to make sure I got the right one. Springs are cheap.

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...then that deformation of the rim is towards the left side of the rim. So, there should be a huge step at that side of the breech face, if it was to cause so much deformation. I mean look at the depth of that ledge there, it should be close to 1 mm. What was the manufacturer of those pistols which had a step on their breech face? We were discussing that some time ago.

My one NH has this step on the breech face, maybe 5 - 6 thou above rest of face. It will leave a slight mark on the brass.

I am wondering about this... intentional or breech face not finished properly?

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I am wondering about this... intentional or breech face not finished properly?

Machining flaw. Smith & Wesson had this issue early on with their 1911 variant/clones, and tried to pass it off as a non-issue... but they've since changed their stance on it, or so it's rumored... and they're repairing the slides due to popular demand, I suppose.

On examining my Kimbers slide it has a small step on the left side(oposite the ejection port) just as several of you stated. Is there any way to have it machined down and not effect the operation of the firearm?

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"By the case pressed hard against the breechface under pressure. Bare slide. remove the extractor to lessen resistance. Place a case into normal position and push it hard against the breechface. Will the firing pin protrude? No. Can't."

If you're correct, and I don't believe you are... if the FP can't protrude when the case is slammed back hard against the breech face then there would be no FP drag marks at all.

The FP can protrude into the softer primer material when the case is slammed back into the breech face. Then as the barrel unlocks, it drags across the FP as the FP retracts, thus making the mark.

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"Looking at the next batch of photos in Post #25...The top one appears to be a second strike mark, while the others look like tadpole tail drag marks."

I understand what you're saying here, but Dave and I think it's still FP drag.

Like I said in my first post, I believe the barrel held lock-up a fraction longer, the FP is starting to retract, where in the pics 2 & 3 it hasn't. While the FP is on it's way to retracting, it drags on the primer as the barrel is starting to unlock. The FP has pulled back enough out of the deep primer strike that it made, it just hasn't retracted enough to cleanly miss the primer altogether.

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"It could be that the pin is against the primer during the whole process, and when the gap opens... just walks out."

That's my and Dave's thinking above... kinda, sorta, roughly...

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"...the pin is trapped by the lower wall of the port and the depth of the indentation in the primer.

Forced against the lower wall of the port by this vertical force... it can't retract.

To demonstrate... remove the firing pin spring and insert the pin so that it protrudes. Push down on the top of the pin. That's the mechanism at work."

Now you're mixing apples and oranges a bit.

Look at primer strikes, they are curved, not flat, the same as the nose on the FP. Now, since we're talking about angles, not something pushing flat against something, it'll force the pin back, not apply full side pressure as what your demonstration would show.

The primer material is pretty soft, that's why the drag marks. If it was, say softer in the middle exactly where the primer strikes, then harder on the edge of the primer, than I would agree, and there wouldn't be drag marks, as the material would be too hard.

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"M1 Garands and M-14 rifles have floating firing pins without springs. When the rifle feeds and goes to battery at full speed, the firing pin will mark the primer lightly."

M-16's will also do the same thing, as their pins are floating as well. But 1911's do not have floating FP's.

sasu, do all your rounds have a FP drag mark? or is it sporadic?

If there are no consistent FP drag marks on most every case, then it's a very much tell tale sign that it's still a FP drag mark, and not a second strike.

As second strikes will be more consistent, as Tuner pointed as his method of knowing when to change FP springs.

All of them have this mark, some smaller, some bigger, but it is there on every primer.

Neimi is right. The dent is caused by an imperfect bolt face. My PT1911 does the same thing. At first I was concerned, but the gun functions perfectly and besides, I can tell exactly how many times each case has been reloaded. The first three round out of the gun showed firing pin drag marks, but that cleared up and I have not had any drag marks since. It just takes time for these things to break in.

As soon as I saw those pictures on page one I knew you had a SW1911.

I just checked your other posts, you said you had a S&W in another thread. (I found it odd that the brand was not mentioned in this thread)

I too have a SW1911PD and that is how I recognized the pictures. My gun does that too. It is not the firing pin.* I thought is was for the longest time but then, when cleaning the breach face I noticed a glint near the firing pin hole. You can only see it if the light is right. The breach has a small burr at the top of that hole. That is what makes that mark.

BTW, great photos.

*EDIT: I just looked at my breach face and no longer believe the above statement to be correct. Pictures to follow.

That's a heck of a good idea, sasu, that about shooting through a loupe (magnifier). It's never occured to me to try that and I've been frustrated with the closeup performance of cameras after my late great Sony FD71 that made images measured in centibytes but could focus on things that were actually pressing on the lens.

Someone make a photo of this "ledge" or whatever it is on the breechface of Smith 1911 pistols, OK?

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Someone make a photo of this "ledge" or whatever it is on the breechface of Smith 1911 pistols, OK? Look by the A's.

Trying to make sense of the debate on second strike/ drag is quite interesting. If it is a FP dragging, what causes it to stick? Dirty tunnel? Here's where I lose the dragging theory: (and my take on what happens... which has been wrong before so please correct me where needed)

When the FP strikes, it doesn't just hang around to see what happened. It is moving against resistive force in the form of a spring. Hammer induces enough energy to overcome the resistance until the strike. At the point of the strike, the transferred energy is gone. All that's left is a little bit for the "opposite but equal" side of the equation. When the FP strikes the primer, it rebounds/bounces and is immediately yanked backwards by all the resistive force from the FP spring. The rebound impulse merely gets it moving before the spring can take over.

At impact, the primer ignites, then the powder, and as we've seen from the Tripp video, the slide starts moving first. That little bit of movement gives the spring time to fully retract the FP from the primer before the barrel starts to unlock. So what could make the FP hang out long enough to be affected by (even a early) barrel unlocking? The idea that the spring indeed removes the FP from the primer, and it rebounds again from the FPS, then restrikes the primer as the barrel unlocks seems more plausible to me. That's how the downward force acts to pinch the FP, causing the drag mark. Otherwise, there'd have to be downward force on the case at the moment of the pin's first strike.

Quote: If it is a FP dragging, what causes it to stick? Dirty tunnel?

It's not actually "sticking" in the tunnel. It's bouncing back and forth as the slide moves, and moving in and out of the port as the position of the case allows. See the ammunition in the cutaway magazine in Tripp's stop-action video for a clue as to what the pin does.

If the pin gets back out of the port at the right instant... while the barrel is dropping... and knocks a second dent in the primer... it then creates a drag because it captures the firing pin. Imagine a stick in a pipe that's prodtruding through a wall. In-out-in-out... easy. Slip it out and hang a heavy weight on the end of it... and it becomes harder to retract back into the pipe.

Inertia is a funny thing. It causes objects to do strange tricks.

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Inertia is a funny thing. It causes objects to do strange tricks.

So would using a titanium firing pin stop the problem?

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So would using a titanium firing pin stop the problem?

Yes. So would a firing pin spring of the correct strength. Browning's specs are important.

While we're on it... This is another reason that I prefer Series 80-type firing pins. One of the few modern changes that I really like. They're steel, and because of the hourglass cutout for the slide plunger... a little lighter. It provides an extra measure of bounce resistance without resorting to exotic materials that are often less than suitable for long-term use.

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If it is a FP dragging, what causes it to stick?

The FP is not sticking, it's the barrel is unlocking too soon, and the FP is still out while the barrel is going down... which in essence is dragging the case across the FP.

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it's the barrel is unlocking too soon,

The barrel doesn't... can't... unlock until the bullet is gone and pressures fall. While the pressure is still on, the firing pin can't get through the port any farther than the indent on the primer. Once the slide draws the barrel back far enough to start linkdown... and the bullet is gone... the extractor claw starts to engage the case rim, and THEN there's enough gap for the firing pin to poke out. Once it gets back out, and hit the primer while the case is being pulled down... it makes the drag mark. If it simply runs out under inertia during the most violent phase of slide recoil... and then rebounds under the influence of its spring... there's a second-strike mark without the tadpole tail. Sometimes both marks are seen. Most often it starts with a second strike and evolves into the drag mark because the initial marking is unnoticed or ignored.

I guess the two opinions of Wichaka and Tuner are kinda confusing me...What I'm getting is that one opinion feels the case moves while the fp is still through the hole and in contact with the primer on the initial strike (drag). The downward motion of the case just pinches the FP's nose between the primer dent and the fp hole.

The other opines that the fp makes the strike and then due to a weak spring bounces back into the same dent in the primer (second strike). During the unlocking phase, when the barrel starts to move and the fp is contacting the primer for the second time is when the tadpole tail marks occur.

Here's why I asked what made the fp 'stick': The FP spring is moving the fp away from the primer during the initial pressure impetus, before the bullet has cleared the barrel. Unless there was something to hold it in place, it's long gone before the case ever starts dropping. That's why it makes more sense to me that the FP is getting back through the fp hole a second time.

If it was timing issue, related to unlocking early, wouldn't that also create feeding issues as it tried to lock up late?

You're too technical again...r ead what I said... the FP is still out while the barrel is going down, which creates the drag mark. I didn't say anything about pressures etc. It's unlocking and starting down before the FP has a chance to retract.

Think about it, it'll come to ya...

So you're not specifying when the fp is out, just that it is. Okay, I can understand that.

For 1 min. and 2$ (plus mailing if it isn't local) you can drop in a new spring, eh?

So, berkbw condensed this entire 6-page discussion down to "drop in a new spring,eh"!

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So you're not specifying when the fp is out, just that it is. Okay, I can understand that.

Go back and read all my posts, it's very explicit when the FP is out.

You may look at changing the FP spring as well as the recoil spring, but I'd look at the FP spring first.

...how many forum members does it take to change a spring...

These are marks made by the firing pin when it strikes the primer of the bullet and remains there for a fraction of a second. The fraction of a second that the pin remains in contact with the primer in conjunction with the recoil of the gun creates what are called firing pin drag marks. The recoil of the firearm forces the barrel back & down thereby scratching the primer of the cartridge against the firing pin. Some handguns, such as the Glock, have a very unique pattern and are easily identified.

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...how many forum members does it take to change a spring...

I supose only one, but, needs discussion first...

Hate to spend that extra 2 bucks. Gotta make sure there is no other way. Haha

A second strike of a FP under inertia will not leave a dent in the primer no where near what pic 1 shows.

If you lock the bolt back on a AR-15, load a mag in and release the bolt, it'll slam forward, chamber a round, and leave a small ding on the primer from the floating FP, yet no where near enough to fire off a round.

That ding is caused from the floating FP, which is caused by the full force of the bolt coming to an abrupt stop, which has more force than a FP under inertia on a 1911 slide just starting to come back during the first part of

cycling. Tuner said;
"The barrel starts to tilt, beginning primary extraction. Now we have a growing gap between the case rim and the breechface. As the barrel heads for full linkdown, the case has started to drop as the extractor starts to yank it free of the chamber. Now, we have the location for the second strike... which is roughly the diameter of the pin, and that's just about where the mark is. The firing pin obeys Newton and stand still while the slide is literally yanked out from under it.

The firing pin standing still at this moment in time, when the slide is just starting to move, does not yet have the force to yank the pin out from under it and create the mark left on the primer, as in pic 1. It wouldn't have enough power to make that kind of mark even if the was no FP spring in the gun.

FP drag is usually caused most likely by a weak FP spring, but one of those EGW FP stops, can hold the works locked up a tad bit longer and help the situation as well. But the quick fix is the FP spring.

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If you lock the bolt back on a AR-15, load a mag in and release the bolt, it'll slam forward, chamber a round, and leave a small ding on the primer from the floating FP, yet no where near enough to fire off a round.

Yes... And?

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That ding is caused from the floating FP, which is caused by the full force of the bolt coming to an abrupt stop

Which nowise can duplicate the violence of a 14-ounce slide under full recoil in a 1911 pistol. If you could see it, you may be surprised at how hard, and how many times the firing pin bounces in and out of the port during one cycle.

It only takes one forum member to change the firing pin spring, but the member has to let this thread run it's course first or suffer the full wrath of the force upon themself.

Possibly even be sentenced to own only black tupperware in the future!

I got hold of the gun long enough to take photos of the breechface.

Here you can see the ledge.

DSCN16420001.jpg

It looks like the breechface is tilted sideways, but hard to tell for sure without a straightedge.

The marks here might indicate that the barrel hood hits the breechface only on the righthand side. In fact the muzzle end of the barrel has scuff marks only on one side, which might also indicate the barrel being twisted sideways.

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If you could see it, you may be surprised at how hard, and how many times the firing pin bounces in and out of the port during one cycle.

...and the price of tea in China is what?

It doesn't matter how many times the FP bounces in and out "during the cycle", what we are talking about is the moment that the round is fired, and the FP is still out... not the whole cycle process. At the moment that FP drag occurrs, there's not enough force for the FP to make a second strike.

Apples and Oranges.

Think about it some more... it'll come to ya.

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Think about it some more... it'll come to ya.

Oh, I have. Ever since I first saw it happen... about 40 years ago.

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Oh, I have. Ever since I first saw it happen... about 40 years ago.

Now you're contradicting yourself,

You said;
"If you could see it, you may be surprised at how hard, and how many times the firing pin bounces in and out of the port during one cycle."

First you said if you COULD see it, now you're saying you CAN see it... which one is it? And how can one see the FP do this?

Also like I said you're talking Apples & Oranges.

It doesn't matter how many times the FP bounces in and out "during the cycle", what we are talking about is the moment that the round is fired, and the FP is still out... not the whole cycle process. At the moment that FP drag occurs, there's not enough force for the FP to make a second strike.

I can tell you and the folks on this forum, from training and experience in the area of firearm forensics, your theory is just that, a theory and no more. It would never hold up in court, because it can't be done.

Take a primered case, chamber it, then drop a 1911 barrel first from X feet,you pick the height. From the force of the abrupt stop of the gun hitting the ground, the firing pin may detonate the primer, but you can not replicate that force in your hand without something actually contacting the FP... in the this case, the hammer. You will not get what you see in pic 1, from what you're saying. It can only be done if the firing pin is already out, OR there's a second direct hit on the FP itself to force it forward, to create what you see.

Keep thinking about it... it'll come to ya!