645 FTF

[RoyK]

Hi all. I have a nice 645 that has been back to S&W once before for this problem. It seems the decocking lever retaining screw on the right side of the frame works loose. Thus preventing the pistol from cycling. Hence the complete FTF! What retains the screw in the lever on the pistol? Torque specs? Lock Tight? Does over zealous or improper cleaning affect screw retention? This is a good looking, nice shooting pistol that seems to have either a serious mechanical problem or a serious owner problem! Thanks.

 

[Sevens]

A short term "instant" fix is to unscrew it and remove the lever. It is only the two pieces (lever and screw) and it does not serve the master in any way. This quick temporary fix will also help you isolate the problem to ensure that your theory is correct. (I'm not sure I agree that it is)

Most have found that if the early ambi-lever like the one on your 645 was never taken off outside of the factory, it is never a problem. Once you do however, it'll never stay on again until you use some thread locker or Loc-Tite on it.

 

[flagman1776]

EDIT: My old duty 645 does not have any screw. It was the Dept Armourer's "class gun" which he then carried for a while. I bought it from him when he moved on to something else.
The additional 645 I bought recently has the allen headed screw. I'll post pictures up later.

My original post: I've never had mine loosen. If it did, I'd use BLUE LocTite and put a small drip on the threads & let it dry. Then reassemble. The LT will not stop assembly but will prevent it backing out.

Do not use RED. Too long a story & off topic to post here... but it involves a pipe wrench & a 15 foot cheater bar (pipe).

 

[N4KVE]

I recently bought an early 645 that had this problem before I purchased it. The original owner fixed it by using the levers from a 4506. GARY

 

[Laketime]

I know early on they switched to an oversize looking Phillips head screw to replace the original screw due to problems.Is this what you have or is it the original hex head screw?.

 

[Bruce51]

Clean, polish, lubricate.

The screw being tight on the lever should not create a FTF.

If the lever can be pushed above the center line then it could cause a drag on the firing pin. You can test this by checking if the drum drags on the FP if you push up on the lever and then try to push in the FP.

I will post a link to a previous thread. Basically the hammer would drop to half cock rather than hit the FP.

It would seem to be a case of hammer drag or lack of lubrication, slowing lock time, causing the hammer to catch in the half cock position.

Check your hammer for rubbing, clean and lubricate all the contact surfaces.

I found my problem by repeatedly dry firing the gun until I saw it stop at half cock several times.

No problems since I replaced the hammer and properly lubricated the parts.

Hammer sides can be polished if drag marks are present.

http://smith-wessonforum.com/s-w-smithing/363438-745-ftf-hammer-half-cock.html

BLM

 

[RoyK]

or is it the original hex head screw?. From Laketime.
It is the original hex head screw.

 

[Laketime]

or is it the original hex head screw?. From Laketime.
It is the original hex head screw.

All I can remember when I bought mine back then was an article about the switch.I asked my LGS if they had the hex screw model,and stated that all of their inventory had been sent back and fitted with the new stupid looking Phillips head screw.I remember this issue being a function problem somehow.Its been a long time,and Im getting older so I cant give better details for you.

 

[flagman1776]

Photo shoot:

Original safety with allen head screw.
My take: with such a small allen head screw, probably difficult to get enough torque on the screw.

Safety lever on my Duty M645... (Had been Dept Armorer's S&W school gun... possibly safety lever changed out before I got it?? Supposedly had all the upgrades possible.)

 

[Laketime]

Photo shoot:

Original safety with allen head screw.
My take: with such a small allen head screw, probably difficult to get enough torque on the screw.

Safety lever on my Duty M645... (Had been Dept Armorer's S&W school gun... possibly safety lever changed out before I got it?? Supposedly had all the upgrades possible.)

That second pic looks like the 4506 version.

 

[N4KVE]

That's exactly how my 645 looks. The previous owner changed it out for a 4506 set up. GARY

 

[flagman1776]

Picture's worth 1000 words...

 

[Craig19]

It's amazing how much better the 3rd gen safety looks. It looks more "finished"

 

[RoyK]

Good news and bad news......Good news is there is a fix! Bad news is will S&W step up? This has been very enlightening. Thanks to all.