FN FNX 40 Trouble

Sledgehammer45 · Feb 15, 2019

Revised: FN FNX 40 Trouble

Hey All,

I took my fnx 40 to the range at Myrtle Grove this afternoon and ran into some trouble. First 4-5 mags went through without a hitch. Casual shooting, no rapid fire or extreme conditions (temp maybe hit 70?). Then the it would not fire almost every other round. I thought maybe I was "limp-wristing" it and tightened my grip. No dice. I considered maybe ammo did not give enough blow back to properly cock the hammer. I tried manually cycling the slide and cocking the hammer. Still temper-mental. Cycling the misfired round out I saw there was no impact on the primer at all. Looking at the slide I pressed on the back of the firing pin as far as it would go and it doesn't seem to be able to reach out the other end. I'm thinking a broken firing pin?

Also, the double-action is not working. When it was working "properly" beforehand, I had to manually cock the hammer.

Has anyone had similar problems (or solutions) similar to these with FN hammer fire pistols? Appreciate the help!

~Sledgehammer45

craftsman_69 · Feb 15, 2019

Mine is still rock solid but when I bought it used I noticed the firing pin was not protruding proud as it should. I completely disassembled an found a ton of trash in the firing pin channel. Cleaning it corrected this. The safety lever removal was the hardest part.

Sledgehammer45 · Feb 15, 2019

Hope it is that simple. Thanks

Boats · Feb 15, 2019

Let me guess, you are using a high thumbs forward grip?

If you are riding the thumb safety, or if your thumb is slightly underneath it and nudging it up slightly, you are engaging the firing pin safety, which is touchy and activates much sooner than the trigger safety or decocker.

Try firing it while mindfully keeping your thumb away from the thumb safety. Bet your lack of primer strike goes away.

Pressing on the firing pin will not allow the pin to protrude, you have to depress the firing pin safety plunger before pushing on firing pin (similar to series 80 1911s). If you were getting a misfire every other round then the firing pin is probably fine. Bent and broken firing pins don't fix themselves

bigjohn · Feb 16, 2019

I’ve had a few that built up trash in the firing pin channel. Most times, brake cleaner sprayed thru it fixed it with out taking it apart

Sledgehammer45 · Feb 16, 2019

Boats said:
Let me guess, you are using a high thumbs forward grip?

If you are riding the thumb safety, or if your thumb is slightly underneath it and nudging it up slightly, you are engaging the firing pin safety, which is touchy and activates much sooner than the trigger safety or decocker.

Try firing it while mindfully keeping your thumb away from the thumb safety. Bet your lack of primer strike goes away.

Pressing on the firing pin will not allow the pin to protrude, you have to depress the firing pin safety plunger before pushing on firing pin (similar to series 80 1911s). If you were getting a misfire every other round then the firing pin is probably fine. Bent and broken firing pins don't fix themselves

Makes sense. That is my standard grip style. I will have to test that out. Thanks

Sledgehammer45 · Feb 16, 2019

bigjohn said:
I’ve had a few that built up trash in the firing pin channel. Most times, brake cleaner sprayed thru it fixed it with out taking it apart

Thank you

Sledgehammer45 · Feb 16, 2019

I've disassembled and cleaned the firing pin channel. Have yet to test it out. Crossing fingers.

FN FNX 40 Trouble

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