Loose firing-pin-stop caused a failure-to-fire

[Mike_Fontenot]

I fit two FPSs and what I recall is that I only had to remove a small amount of steel on the sides of the protrusion, so the FPS would go into the space where the firing pin sits.  I didn't reduce the thickness of the FPS at all.

Thanks for that info.

[Hermit]

My fps was loose but not horribly loose on my st2 the egw took a little bit of fitting  most of it was for the bomar cut though.

What's the "bomar cut"?  Is that the area on the lower right-hand side of the FPS that is missing on the "Series 80" FPS's compared to the "Series 70" FPS's?

Its the dovetail cut for the rear target sights on the stainless target II I used the 70 series stop so the feeling pin stop button doesn't get stuck in the hole of the 80 stop if I have a little pressure on the grip safety when I pull the slide

[Mike_Fontenot]

[...]
Its the dovetail cut for the rear target sights on the stainless target II.  I used the 70 series stop so the feeling [firing?] pin stop button doesn't get stuck in the hole of the 80 stop if I have a little pressure on the grip safety when I pull the slide

I'm still not understanding.  I think I've got the same "dovetail cut" for my rear sights also, except that I've got fixed sights (Eclipse Custom II).  But I haven't been able to picture how that dovetail cut can interfere with anything.  And I don't know what you mean by the "firing pin stop button", or "getting stuck in the hole of the 80 stop" if you're compressing the grip lever a little.  I know that compressing the grip lever causes the small pin to rise out of the top of the frame, and press upward on the firing pin block plunger (which "unblocks" the firing pin channel), but I don't yet see how the dovetail cut is involved.  (I HAVE heard that, in order to remove the firing pin block plunger and spring, you have to remove the rear sights, but fortunately I haven't had to do that, so I don't understand all those details yet.)  Can you elaborate a little more?

[Hermit]

i need to stop posting in the mornings....heres some pictures

green circle is where the 80 series stop is cut out



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[Hermit]

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[sqlbullet]

To clarify, it isn't so much the dovetail cut, as the relief that is needed at the rear of the slide for the target sight assembly.

[Mike_Fontenot]

OK, I think I get it now.  And my fixed sights don't have that extra cut in the very rear of the slide, aft of the dovetail cut, that the adjustable sights have.

[Mike_Fontenot]

Update:  I spent most of Friday filing my new oversized, flat-bottomed FPS to fit.  Before any filing, the FPS wouldn't even begin to slide into the slots.  Almost all of the day, the progress was very slow ... but slowly I was able to slide it further up into the slots.  Most of that time, I was just reducing the overall width.  But eventually I started spending more time reducing the thickness of the edges that fit into the slots, and I think I should have done a little more of that sooner.  And, even though I was well forewarned, in the last set of a few swipes, the FPS went from still not being able to go all the way in, to being a bit looser than I was hoping for.  It is still much tighter than the one it's replacing, though, and I suspect it'll be fine ... it worked without any problem yesterday at the range.  Since the whole part, including shipping, only cost me about $20, I may order another one, just in case this one ever has the same problem, and I need to get a still tighter fit.  After a few more tries, I may actually learn how to do it pretty well!

I decided to leave the bottom essentially completely flat ... I just gave the edge a few swipes across a whetstone, to remove any tiny burrs, and smooth it a bit ... there is still no visible radius to the eye.  No problems with the cycling yesterday, but I also couldn't really tell any difference in the way the gun felt when firing, or in the distance the brass was thrown.  I haven't examined the primer craters yet, to see if the firing pin wipes have been reduced any.

[Mike_Fontenot]

A new update:

I decided to try again fitting another new flat-bottomed EGW FPS.  One difference is that I decided early on to remove the extractor, and do the fit first without it, and then once that's done, reinsert it, and do any additional fitting necessary.

With the extractor out, I filed even more carefully than before (almost all to reduce the total width), but had the same outcome: I finally got it about half-way in, and then pushed harder than I had been pushing, and the FPS got by the "tight-point" and was then immediately too loose further in.

BUT, fortunately, I discovered what I should have discovered right at the beginning: the FPS wouldn't fit into the extractor groove at all ... the tab on the FPS was thicker than the extractor groove.  So I re-inserted the extractor, and SLOWLY started reducing the thickness of that FPS tab.  And at some point, I again pushed harder than I thought should be necessary, and the FPS then slid in nicely, with just the amount of tightness at the higher levels that I wanted.

I haven't test-fired it yet, but with dry-firing, the firing pin returns nicely back into the hole.  I think it's fixed, but only time (and rounds fired) will tell for sure.

[The_Shadow]

Mike, Good for you...anticipating the range reports!

[sqlbullet]

Glad it is getting there.

[10mmfan]

Two of the four I've done have been a little loose but have been functional but I think it's time to try again so I ordered two more.

[Mike_Fontenot]

UPDATE:

I went to the range this morning, and fired two mags without any problems.  I'm declaring victory, unless and until my gun misbehaves in the future.  Maybe I'll even be able to start ASSUMING it will work every time I fire it!