What is the REAL test for revolver timing?

[roar]

Thanks for the replies everyone.

If it works well at a normal trigger speed I don't see any reason to be concerned. I'll also point out that the 442 is considered a "pocket pistol" by many and that additional slack in the action may mean that it will function perfectly even when it's accumulated some lint.

I agree with this

My thinking is, if it's "loose" now it sure isn't going to get "tighter" with use. If I was positive that it wasn't like this when I sent it in you can bet I would say something if it came back like this after being "fixed", for unrelated issues or not.

And I also agree with this...

I was taught at the S&W factory revolver school that you slowly thumb cock the empty revolver. With the hammer back in the cocked position you give the cylinder an nudge and if you hear the cylinder stop click into position the revolver suffers from DCU or doesn't carry up. It's been a few years but a revolver with DCU on any cylinder notch was considered defective and repair was in order. The revolver was not designed to require speedy manipulation to lock up correctly. DCU usually gets worse over time and is fairly easy to repair.

I usually pass on a revolver with DCU unless priced low enough to repair after purchase.

The old S&W factory "51 PROBLEMS" manual confirms what akviper said. I know that a lot of people don't care that a S&W revolver DCUs as long as inertia carries the cylinder into position, but per the factory, it is a defect. I pass on DCU S&W revolvers unless I think I can easily fix the problem. During the '70s and 80s I purchased several new S&Ws that DCU. IMHO S&W has gotten a lot better at this in recent years. I have S&W revolvers manufactuerd between 1972 and 2009. All of my S&W revolvers carry up properly. I had occassion to have two of my revolvers worked on at the factory a couple years ago. Both time up as akviper and the "51 PROBLEMS" manual say they should. ymmv

Tomorrow morning I am going to call S&W back and let them know whats going on. My 442 definitely has never had this problem before. It is frustrating because my 442 came back with the endshake and open/close issue completely fixed. They switched out barrels for some reason (now I have a "newer" style with different rollmark, pretty cool), and switched out the ejector rod which was showing wear. They also gave me some new sideplate screws to replace a few that I messed up slightly despite having the proper screwdriver. Everything was absolutely perfect, until I discovered this stupid DCU problem.

I still have a few questions regarding DCU. Is it considered a problem if it happens ever at all under any circumstance? I am just wondering because I can almost see how this would have been considered a pass, if you work the action even below normal "fast" speed it will lock up. I really have to pull the trigger slow to make it fail to lock up.

I am just afraid of calling them and having them tell me "Well don't pull the trigger so slow!" or "Well you aren't supposed to stage the trigger!"

 

[Rock185]

roar, IMHO, if somebody at S&W tells you, "don't pull the trigger so slowly" or "don't stage the trigger", they are either uninformed, just trying to blow you off, or both. With the S&W, you should be able to "stage" the trigger or pull it as slowly as you want and the cylinder should still carry up/time up properly. Since this discussion started, I looked in Mr. Kuhnhausen's S&W shop manual to see what he might have to say on this issue. In the section on checking basic action timing, Mr. Kuhnhausen says, " The most important timing requirement is that the cylinder stop must lock the cylinder before hammer release". I have and use four of Mr. Kuhnhausen's manuals and have come to trust the information contained in them. I don't have a 442, but the three 642s and one 640 in use in my family all lock the cylider into alignment with the barrel before the hammer falls in slow DA, even with a light drag on the cylinder,etc. My 640 has been in use for over 15 years now and still carries up properly.

Colt revolvers have been mentioned. The Python, and older pre MKIII Troopers, work differently than the Smiths. They are designed such that they do not actually lock the cylinder into alignment with the barrel, until the trigger is actually pulled. So, if the Python/older Trooper cylinder is not actually locked into position in slow DA or SA, this is not necessarily an out-of-time situation. When operating correctly, pulling the trigger will raise the hand and bring the cylinder into alignment as the hammer falls,etc.

While I much prefer the S&W action, I don't pretend to know which of these systems is "better", but they do operate differently. ymmv

 

[roar]

Hey Rock185,

Thanks for responding, and I completely agree with your sentiments regarding proper function and so on. The person that I talked to at S&W yesterday was fully understanding and very apologetic for me having to send it right back in for the new timing problem. He stated that J frames have less room for error when being adjusted for proper timing.

 

[paladin42]

There has to be some spent brass in the cylinder to correctly check the timing. Otherwise, the cylinder star and the cylinder may not be locked together and may not be aligned properly. The hand pushes the cylinder star, not the cylinder.

 

[haggis]

Some of this confusion is related to the difference between "locked" and "carryup". Carryup is when the cylinder stop locks into a stop notch on the cylinder before the hammer or trigger reaches its rearmost position. Both S&W and older Colt revolvers should both do this on a properly timed gun.

On a S&W, a carried-up condition is also the same as locked - cylinder rotation will not get any more fixed from the carryup point due to being locked by the stop plus the width of the hand.

On a Colt, the action is not locked until the trigger is at its rearmost position. The hand pushes the cylinder tight up against the stop resulting in no rotational motion at all, compared to the slight motion of the S&W.

These differences in locking action are the reason Colt's barrel/cylinder alignment must be checked with the trigger back and the hammer down after the trigger is pulled, while alignment on the S&W can be checked with the system at rest.

BTW, none of this discussion about carryup and locking means anything if the barrel and each cylinder chamber are not sufficiently co-linear after lockup. So buy a good range rod if you're checking all the other stuff before buying a used revolver.

Buck

 

[policerevolvercollector]

I decided to bring this thread back to life because I recently bought a M&P from the late '40s that does not "carry up" occasionally when the hammer is pulled back VERY slowly as indicated in the earlier posts. It never fails in DA or in single action at normal speed.

I was concerned until I realized that it functions perfectly in any ordinary shooting mode. As a control group, I pulled out 6 random S&W revolvers out of the safe and was able to duplicate this behavior in four of the guns if I tried hard enough including one with an extremely low round count.

I'm not suggesting that this shouldn't be addressed if it affects the revolver's performance & safety of course. However, it is easy to overthink and worry about it even when it does not interfere with the gun's functionality.

My Model 12-2 suffered from this ailment. A thorough cleaning solved the problem.

Best,
Charles