The blueprint spec for the 1911 firing pin is 2.296“ +006”-.000”
So the pin is a few thou short. But, series 80 systems can be mistimed so the firing pin block is not moved to clear the firing pin. The timing test is to check to make sure the gun is empty, apply the thumb safety, squeeze the trigger and push on the firing pin. It should be free to move at this point. Use a pin to attempt to move the firing pin. If the firing pin is still blocked when the trigger is pulled with the thumb safety engaged the series 80 mechanism is broken, mis installed or it is incorrectly disabled.
Joe

 

The timing test is to check to make sure the gun is empty, apply the thumb safety, squeeze the trigger and push on the firing pin. It should be free to move at this point.

Why would you perform the test with the safety engaged? As long as the firing pin is free when the trigger is at full rearward travel, S80 is going to work as intended.

 

I'd guess the linkage levers are not in right or missing. With the slide off, grasp the pistol normally but hold down the hammer - pull the trigger and see a lever rise up that would depress the FP safety plunger and free the firing pin if the slide were on the frame. You have to push the lever down to install the slide. These levers should be right from the factory but I suppose wear is a possibility especially on an older pistol like that.

 

Do the above test. Then back off the overtravel screw and try it a gain.

 

I would guess there is a much better chance that the two levers in the frame were assembled incorrectly the last time the gun was taken down for cleaning. The functioning of the Series 80 firing pin levers can be checked with the slide off and the hammer forward just by squeezing the trigger. The lever on the top of the frame will rise if everything is assembled correctly. Everything WILL fit together even if assembled incorrectly.

 

I'd guess the linkage levers are not in right or missing. With the slide off, grasp the pistol normally but hold down the hammer - pull the trigger and see a lever rise up that would depress the FP safety plunger and free the firing pin if the slide were on the frame. You have to push the lever down to install the slide. These levers should be right from the factory but I suppose wear is a possibility especially on an older pistol like that.

Unfortunately, the lever for the FP safety is it not lifting when testing it this way. Which is leading me to believe the levers were assembled incorrectly. I had a friend who tore down this pistol and completely cleaned and rebuilt it from the ground up. It might be possible it was put together incorrectly. Would you be able to recommend any step-by-step instructions or videos on how to fix this issue. As it stands, the only mechanism that moves while performing this test is circled in red on the attached picture.

 

Anxiously awaiting the outcome of this problem......must be in the series 80 linkages somewhere....tearing down the receiver will tell the tale. Is it me or does it look like that extractor has seen a few hot suppers?

 

Every time I have seen a pin blocked by the FPS plunger the plunger will have gouges where the pin slammed into it. It looks like someone installed a pin oversized in dia. and it's hitting the slide breechface. Need to do some careful measuring. There's a good deal of variation on pin diameters and slide bores so they won't drop in a lot of times.

 

Drail, the gouges you note were most likely due to a timing issue of the plunger lift. Possibly even allowing firing pin excursion enough to fire the round. In this OP’s case I suspect the assembly issue never lifted the plunger so the firing pin was completely blocked with full pin to plunger contact. That would prevent the gouging caused by partial contact.
Joe

 

I had the same problem with a Series 80 Colt the first time I did a Detail Strip. I put one part of the FPS backwards / inverted. I took everything apart and reassembled it and then it passed the pencil test.

Every time now after a Detail Strip of a S80 the pencil test is performed. Of course if its a basic Field Strip then the pencil test is unnecessary.

 

The three parts that are grey in the diagram is the culprit.

 

The movement of the trigger during pretravel and taking up remaining slack till firm contact with the disconnector and blocked sear is when the firing pin block should be clear of the firing pin. Any delay in the blocking plunger movement past this point may be in the range of partial firing pin obstruction and misfire. This is where the gouging and peening of the firing pin blocking plunger occurs. Not a condition I want if I am depending on a weapon in an emergency.
Joe

 

Maybe it's me, the OP shows the measurement of the firing pin being 2.2605". Spec is 2.296" +.006, that's at least .036" short, over 1/32" of an inch. Does that not matter?

 

Yes it could, however the 1911 firing pin is an inertia type which strikes the primer, not mechanical. The fact that the S80 lever doesn't move with a trigger pull is an obvious problem and reason for the failure.

LOG

 

Getting the Series 80 frame parts back in place is a bit tedious but not all that difficult if you use something like a round toothpick to hold the parts in place as you install the sear pin and hammer pin.

 

Burrito.. You are in good hands with Logman. I had similar issues after fitting aftermarket triggers on my Series 80 equipped Commander. If you’re using a trigger with an over travel stop screw, you may be limiting the firing pin safety levers travel to full disengagement of the firing pin block plunger, and require more travel in the levers. I replaced my upper block lever with a #1 lever, and found I still needed more lift by a few thousandths. Log describes a method to gain a bit more lift by placing a weld bead on the lower levers contact point on the trigger bow. It may be what is needed to get the upper lever to lift up to specs, to ensure complete disengagement of the firing pin stop plunger. Look up his threads involving the Series 80 firing pin safety.

 

Thank you THagan.
So I took the plunge and tore apart the receiver. According to the YouTube video (

@ 9:55) that walked me through the tear down, there were only supposed to be 3 components to the sear assembly (Trigger Bar, Sear, and Disconnect). I’ve noticed there is an additional clip and sear spring. Might anyone be familiar with these extra parts?

 

LOG

 

View attachment 653349

LOG

Hi Log,

Thank you for this diagram. Quick question though, am I placing this Gold Cup Lever over the sear spring?

 

Yes.

LOG

 

I did not find a sear depressor lever in my Gold Cup when I took it apart. It is a used gun though I was pretty sure that all the pieces were present. Gun had the odd 4 leaf sear spring installed which I recently replaced.

At some point I should make some aluminum pins to hold the parts in alignment instead of using the round toothpicks. It would probably fit a bit better.

 

Buy a stick of tig aluminum welding rod. Or any welding shop should give you the 3in piece they dont use.

 

SUCCESS!!!
Thank you to everyone for all of your theories and advice. In the end you guys were absolutely right, the issue resided within the receiver and the mechanical levers were not properly aligned. After several attempts at aligning and placing the Gold Cup Lever and Sear Spring win their proper place.. which was an ultimate Pain-In-The-Ass… my grandfathers 1911 now exuberantly passes the pencil test. Shoutout to Log Man for his detailed and prompt responses. This truly is a prideful piece to my family’s collection and I’m proud that it is back in working order. Cheers fellas!