Stubborn 640


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Hawk
April 29, 2007, 04:42 PM
Reading the threads around here got me interested in revolvers - I succumbed to a little 640 pre-lock, 38 SPL only.

The problem is that after cleaning it up, it's just a little bit too tight - takes a moderate shove when opening the cylinder. It only happens some of the time. It took me forever to notice that the ejector rod has a teensy bit of what I think is called "runout". I wasn't noticable until I got the thing all slicked up to where the open cylinder would "spin" for a couple seconds.

It's only a minor annoyance. And may or may not have anything to do with the less than laser straight ejector.

Should I just suck it up or get if fixed? I can't tell if it affects any other function - DAO with a 2" barrel isn't a backdrop against which I could perceive minor accuracy problems - it seems to shoot fine and actually has a surprisingly smooth trigger.

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dbarale
April 29, 2007, 04:47 PM
OK, don't get offended, the ejector is screwed all the way in, right?

Hawk
April 29, 2007, 05:05 PM
Revolver noob, here. Pretty much impossible to offend. :)

Yes, ejector rod screwed in. I had done a search on S&W forum and found someone with a similar issue. Recommendation was to check ejector rod screwed in, screw tight on release latch and frame screw at back of trigger guard.

I did all these before posting.

In all honesty, I couldn't get the ejector rod to "turn" with finger pressure in either direction and assumed this meant it wasn't loose. I haven't dug out the vice-grips yet.

Also, it's way tighter in one of five positions only. I was guessing ejector effective length would effect all equally.

351 WINCHESTER
April 29, 2007, 09:36 PM
Sounds like the tip of the ejector rod may be a little "boogered up". Look closely at the tip. It doesn't sound serious, but sometimes a little "cleaning up with a fine stone doesn't hurt".

Hawk
April 29, 2007, 10:25 PM
It does look a little "rougher" than the ejector on the 57-3. I'll try a little gentle deburring.

Tkys

johnny blaze
April 29, 2007, 10:32 PM
A question on this issue. What is the proper way to remove the rod without really messing up the rod itself?

Old Fuff
April 30, 2007, 02:05 AM
A question on this issue. What is the proper way to remove the rod without really messing up the rod itself?

Brownells (www.brownells.com) sell a special tool for the purpose. Otherwise pull the yoke off of the cylinder assembly, and then clamp the rod in a vise, with a piece of soft wood on each side. Remember to turn the cylinder counter-clockwise, and put two or three empty cases into the chambers to support the extractor stem.

Do this experiment: Hold the cylinder back as far as you can, and then push on the thumb piece and see if the cylinder unlatches easily. Then repeat, but push the cylinder forward before you push on the thumb piece and see if the cylinder is sticky, and/or hard to unlatch.

Hawk
April 30, 2007, 09:30 AM
Ah, Mr. Fuff, the one that inspired me to set down this path to perdition paved with older revolvers...

The 640 has responded well. First, we said a prayer asking forgiveness and vise-gripped the knurled portion of the ejector and gave it a moderate heave counter-clockwise.

When closing the cylinder, right before the ejector rod disappears behind the whatchamacallit, the central portion wasn't as "high" as the one on the 57-3 and there appeared to be a couple of burrs on the knurled portion (one hopes not from the excercise with the vise-grips). Gentle application of a Brownell's fine flat seems to have gotten the thing comfortable.

...still a little stiffer than the 57 but greatly improved. It's still not uniform in that opening from one of the five positions is rougher than the other four but not as pronounced.

I didn't notice any change when holding the cylinder rearward vs pushing forward. Out of curiosity, what would that have indicated?

Old Fuff
April 30, 2007, 11:37 AM
I didn't notice any change when holding the cylinder rearward vs. pushing forward. Out of curiosity, what would that have indicated?

I was looking for a condition called, “end-shake,” which is back & forth movement of the cylinder as opposed to slight rotational play. If end-shake is bad enough the latch can’t push the cylinder’s center rod forward far enough to fully unlock the cylinder and it tends to stick when you try to swing it out.

Another possibility is that the yoke barrel (the part the cylinder revolves on) is slightly bent, and causing the cylinder to bind at a certain point. After insuring the chambers are not loaded, pull the trigger back slightly so that the cylinder stop is no longer holding the cylinder. Then rotate the cylinder and see if you detect any bind.

There are a number of small issues that could be causing your trouble, and they are usually minor. The trouble is that they sometimes require special gauges and fixtures to detect and/or fix. If eyeball examination doesn’t turn up the reason it would probably be best to return the revolver to Smith & Wesson and have it checked out. They of course do have the necessary tooling.

Incidentally, if you do return the gun, they will subject it to a complete examination, and repair not only the condition(s) you brought up, but also any others that they find.

I doubt that it will make you feel any better, but I have – over the years – taken brand new guns out of the box and found they had the problem you describe. It’s a matter of (lacking) quality control and inspection. Fortunately S&W does an excellent job of standing behind their products, and if you contact their customer service department I believe they will send you a shipping label and you can send the revolver back and forth on their dime if that should become necessary.

Hawk
April 30, 2007, 01:03 PM
The 640 coming that way is plausible as it appears hardly used. It came in a pristine blue cardboard box with docs, warrantee card and genuine S&W waxed paper.

It's smooth enough for my tastes at this point. A couple hundred more rounds seems in order before sending it off. It's already ingratiated itself sufficient that I'd miss it.

USBP 1969
October 31, 2007, 12:03 PM
I just found this thread on a "640" search, so I hope it's not too late.

99 % of the time whenever we found an Agent's S&W in the condition you describe he had inadvertently swapped the two round head side plate screws.

My new 642 has a screw / plunger arrangement that's significantly different, so if yours has this newer setup, please disregard.

Hope that helps.

Kent

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