Firing Pin Stop Fitting

Current progress:

Blend undercut trigger guard.

Fit trigger to frame.

Fit hammer, sear, disconnecter.

Trigger job.

Fit and blend grip safety.

Fit firing pin stop.

Fit extractor.

Fit thumb safety.

Fit slide stop.

Do a general de-burring and pre-finish clean up.

Refinish.

Decide on grips.

Install sights.

Test fire.

Adjust ejector.

Lock-tite the grip bushings, trigger overtravel screw, and rear sight set screw.

I spent the morning installing the firing pin stop.  It's critical to get a good fit with this part, because if it's too loose it could fall out, or it could cause the firing pin to get stuck, or it could allow the extractor to "clock," resulting in poor or erratic ejection.  

Here's how it looked when I got started:

I used a hone from an old Lansky knife sharpening kit in order to fit the firing pin stop.  This allowed me to remove very little metal between test fittings while keeping the edges very smooth and polished.  Basically you test fit, stone a few times, mark the part with black magic marker, test fit again, see where the marker has rubbed off, and stone some more.  Repeat for as long as it takes to get the part to be able to mate with the slide.  Then test how the FPS fits with the extractor, insert the extractor into the slide, and see if the whole thing fits together.  If not, determine where it's sticking and address those areas.  

Finally the whole thing is together.  Notice I did not insert the firing pin.  I don't really need it yet, and the snugness of the firing pin stop in the frame is enough to keep it all together without the firing pin holding it in place.  I'll add the firing pin when I start to do some function checks with snap caps, but that's a ways away.  For now, I'll leave the firing pin out for general safety reasons while I continue to fit everything together.

With the extractor and FPS installed, I can see if the pistol will cycle snap caps and even live rounds!  (remember, no firing pin yet, so we can safely cycle live rounds without any chance of a negligent discharge).  

First I wanted to adjust the extractor tension before I tried to feed a snap cap from a magazine.  I pulled out my trusty brass Weigand extractor tension guage, and wouldn't you know, it wouldn't even go under the extractor.  I figured the tension must be way, way too high to begin with.  So I pulled out my flashlight in order to get a better view of what's going on, and...

Disaster.

This is the best picture I could get of the problem.  The breachface is too narrow to accept a .40 caliber shell.  Shit.  This must be a 9mm or .38 Super slide they sent me.  I emailed Bob at Fusion, but haven't heard back yet.  

I'm concerned because there is a good chance I'll have to start completely over with this project.  Hopefully they can simply re-mill the breech face, but we'll see.  I'm a little perturbed they spent so much time mating the .40 barrel to the bushing, and both of those to the slide, and all of that to the frame, and never noticed that the breach face was wrong.  

I'll update when I get Bob's response.  In the meantime, it's possible to keep working on frame components, but if the frame is replaced then that's not a good idea, because all of those components will need to be replaced as well.