645 firing pin sticking

[Messersmith]

My 645's firing pin started sticking (or remaining fully extended) when I dry fire it. Any thoughts on what may be causing this? I've lubed it and it doesn't appear to be excessively dirty. Is it easy to disassemble to clean and inspect or should I take it to a gunsmith?

 

[Messersmith]

My 645's firing pin started sticking (or remaining fully extended) when I dry fire it. Any thoughts on what may be causing this? I've lubed it and it doesn't appear to be excessively dirty. Is it easy to disassemble to clean and inspect or should I take it to a gunsmith?

 

[Bruce51]

The first thing I would do is remove the firing pin and check for dirt and debris. The spring could also be damaged and that will be obvious once it is removed.Check your safety lever for wear on the upper part of the frame. A simple test would be to push the lever up and then see if you can depress the firing pin.The lever can bind the firing pin if it can move upwards.

After you have disassembled the slide from the frame you can remove the firing pin.

To remove the safety lever you must depress the firing pin into the slide.
Then start to push the lever from right to left while rotating the lever downward. When you have cleared the firng pin remove the tool and continue to wiggle the safety lever out of the slide. There is a spring and detent on the lever so don't lose it. Once the lever is removed the firing pin and spring can be removed from the slide and cleaned or replaced. Post again if you have more questions. Bruce

 

[handgunner356]

You'll also need to press in the firing pin safety plunger under the slide in order to move the firing pin. The safety plunger could also be sticking and/or bad spring, it requires removing the rear sight to change.

 

[Messersmith]

Thanks Bruce and Hangdunner. I'll try these steps and see what I can find.

 

[Messersmith]

Ok... I removed the firing pin and spring last night. Both were clean and intact (not broken or bent). I lubed and reassembled everything and still have the same problem.

To get the firing pin to retract, I need to open the slide and push it back slightly (maybe 1/8 inch) with a fair amount of force and cycle the slide then the firing pin fully retracts. The pin doesn't appear to be stuck as solidly as it was before I disasembled and lubed.

Any further suggestions?

 

[rduckwor]

Originally posted by Messersmith:
Ok... I removed the firing pin and spring last night. Both were clean and intact (not broken or bent). I lubed and reassembled everything and still have the same problem.

To get the firing pin to retract, I need to open the slide and push it back slightly (maybe 1/8 inch) with a fair amount of force and cycle the slide then the firing pin fully retracts. The pin doesn't appear to be stuck as solidly as it was before I disasembled and lubed.

Any further suggestions?

What's the round count on the pistol?

Is it possible that it's time for a new FP spring? i.e. The old one is simply too weak to retract the FP following hammer strike?

Good Luck and please let us know as I have a 645 and it's my favorite pin shooter.

Thanks,

RMD

 

[Messersmith]

I bought it used so I don't know how many rounds have been though it. It was in "like new" condition when I bought it and I've only put a few hundred through it myself.

I may try a new spring anyway just to see if that helps.

 

[Bruce51]

I don't know if this is relevant to your gun as I do not know how deep the safety lever cut is on the slide of a 645. I will post the details of the problem with my 745 and you can see for yourself if the same problem applies to your gun. If not at least others will be aware of the safety lever issue as applies to the 745.

I thought I would share some information regarding my S&W 745. As you know this is a first generation pistol made in 1988.

In the past I have had several FTF and a couple of years ago I figured out that the safety lever was jamming the firing pin. The reason this happens is that the milled out area for the lever is very shallow. As the gun cycles the lever can peen the slide. This results in rounded edges on the lever and raised metal on the slide. When the lever can move up beyond being parallel with the slide it will jam the firing pin. I was able to clean up the metal in those areas but as you will see in the photo the slide now has some metal missing from a critical area. Not only was the milled out area too shallow to begin with, but when it was made there was a raised area where the lever rests in the firing position. I had to dremel the raised area to make it level with the rest of the cut.

So for now the gun works as it should. Sometime in the future, unless I can find a new lever I will have to weld more material to the lever to be able to square up the edges. The picture clearly shows that the inside of the lever is becoming more rounded off with use

If any one here ever finds one of these pistols and considers buying it, then the slide and lever should be checked for this problem. It is not hard to check the slide for peening. The lever has to be removed to check for wear. If I had known about this problem I would not have bought this particular gun. I know that there are many out there, who have not had problems. I hope this information is useful, as we do like our pistols to work every time. Actually this is why I now look for Colt 1911's to work with. So many parts and options and so little time. FWIW on my 639 the milled out area is at least three times deeper maybe more. It has fired thousands of rounds with no FTF even with a bad FP spring and a broken ejector.
Bruce

 

[Messersmith]

Thanks for the info Bruce. This is not an issue on my 645.