MODEL 617 CYLINDER AND TRIGGER LOCKING UP

[sdk]

The cylinder in this 617-1 revolver frequently locks up rotationally, usually within the first 30 rounds after starting a new shooting session with a freshly cleaned gun. When this occurs the cylinder is also difficult to swing open and close. I've made sure that there was no residue behind the extractor star and also made sure that the extractor rod is tight. The gap between the forcing cone and the cylinder is more than .004 and the head space behind the cylinder is ample. I sent it to S&W and received the gun back with paperwork stating that they were unable to repeat the problem and made no repairs. After receiving the gun back from S&W I went back to the range and the problem occurred during the first 6 rounds and repeated again after 15 or 20 rounds. After that the problem seemed to stop. This has occurred with both Federal bulk ammo and CCI Mini mags. Another aspect of this gun is that it doesn't have the 2 small extractor dowel pins in the cylinder that locates the extractor star in position with the cylinder. This must be about the time that S&W discontinued them. This revolver was manufactured about 1995. I'm wondering if anyone has had a similar experience. I will be grateful for any help.
S.K.

 

[armorer951]

Can you check the rear gauge? The headspace between the rear of the cylinder and the breechface. Clean/empty gun, insert feeler gauge just below top strap in the area of the hammer nose bushing.

If you are familiar with the term "end shake".....is there any at all?

 

[Fishinfool]

Are loaded cartridges hard to chamber? Many K frame .22's have tight chambers, sometimes making it difficult to fully seat a round, often giving the impression a round is fully seated in the chamber when it is not. This can cause the problems you are experiencing. I have a model 18-3 that does this, but I hate to mess with it (open the chambers slightly), as it is so accurate as is.

Larry

 

[sdk]

Thanks for the replies. Yes I've checked the head space and it's .010/.012. Also, there is no end shake to mention. Maybe .001.
The loaded cartridges are easy to insert and bottom. They go in easier than some of my other K frame 22's.
Thanks again for the replies.
S.K.

 

[sodacan]

Is the ejector rod screwed down fully?

 

[sdk]

Yes it is. I believe that this will be a challenge.
S.K.

 

[Phish]

Could be the ammo you using. Try using different brands. I found using federal lightening doing that so I switched using CCi's.

 

[Wee Hooker]

So will it bind if you dry fire (on #4 wall anchors/snap caps)?
How about if you load only every other round?
Has the gun been apart for trigger work /cleaning at all? (i.e. Could there be something INSIDE the gun gumming up the action.)
Can you see daylight between the cylinder face and forcing cone when it binds?

Sounds silly I know but as a test engineer I can tell you that every bit of evidence can help in an odd diagnosis like this.

 

[Seven High]

It could be that there is some crud in the internals. I would take it apart then clean and lubricate it. It's fairly easy to do.

 

[Tom S.]

Does it matter whether you are shooting single action or double? If the gun only malfunctions during double action shooting, you may be short stroking the trigger or have a timing issue. If it's timing, it may show up single or double action. Also, does it appear to happen on the same charge hole? Using a marker on the outside of the cylinder will give you a frame of reference.

My starting point would be to remove the internals and thoroughly clean everything. A Q-tip type swab will show any burrs left from machining as they will pull strands from the swab. Hit these with a stone to remove. Lightly oil and replace everything. Make sure the firing block is properly placed before trying to put the side plate back in place. If this doesn't resolve the issue, I suspect a timing issue, and do not recommend you try to resolve it yourself.

Good luck, and if you resolve the issue, please let us know as it may help the next guy.

 

[sdk]

Thanks for all the replies. Yes, this has occurred with Federal bulk as well as Mini Mags and quite frankly I don't remember if I tried it on single action shooting but I will definitely try this the next time at the range, hopefully this weekend. Another thing I will try will be firing it using snap caps or #4 drywall anchors.
In the past I've removed cylinders and ejector rods from various revolvers but I'm not quite comfortable removing the side plate at this time and if it comes to that I will bring it to a local gunsmith. I'm still very surprised that S&W was not able to get this problem to occur while they had the gun. Thanks again for the replies.
S.K.

 

[sdk]

Over the weekend I purchased some snap caps (wall anchors from HD) and fired about 60 rounds with them and there was no binding. I then proceeded to fire with Federal bulk and it began binding immediately. I then shined a flashlight from behind the cylinder to check the clearance between the back of the cylinder and the recoil shield and saw an interruption of the clearance which was probably a round that backed out during firing. As I replied to Fishinfool earlier, the rounds fit looser in the cylinder of this gun than in some of the other K frame guns and I believe that rounds backing out of the cylinder may be the cause of this problem. Next weekend I plan to apply some black ink to the recoil shield with a Sharpie to verify that rounds are rubbing against it. If this is the case I'm wondering what the fix would be for it. Thanks to all who have been replying.
S.K.

 

[Phish]

My 617 loves the CCI Blazers but it does shoot just about everything else except for some federals and winchester bulk stuff so the quality in bulk is only so good that is why the stuff is cheap. I picked a CZ rifle last month and shooting the same stuff that I can easily tell the cheap bulk ammo is not all that great. With that I believing the bulk stuff is great for loose chambers for semi autos and lever actions. It pays to get the better stuff for precision guns IMO so hopefully yours gets running good.

 

[Tom S.]

SDK: You haven't mentioned if the cases are difficult to extract or not. You are on the right track in determining the cases are backing out and causing the lock up, but after firing, the cases should contract enough to slide back in the cylinder bore. A tight or rough cylinder bore could be the issue.

If it were my gun, I would start by inspecting each chamber in the cylinder. To do this properly, they will need to be thoroughly cleaned. Many 617's have been reported with rough and/or tight chambers. Some polish them out using various methods and compounds, while others buy a chamber reamer and ream the chambers out. The reamers aren't cheap, around $70+ from Brownells. I would try polishing first and if that helps but doesn't eliminate the problem, then look into buying a reamer.

 

[sdk]

The spent rounds eject easily. I suspect that the rounds that might be binding up are unfired rounds. I have one unfired round from this gun that has scrapes marks on the head. However, I asked myself the same question. Why don't the rounds that slide out simply slide back in rather than bind the cylinder. My theory is at that there is just enough friction between the head of the round and the face of the recoil shield to push the round to the side when the cylinder rotates, causing the round to cock and not retreat back into the cylinder which results in the binding. Right now that's all I can think of. As I said before, I have an unspent round with scrape marks on it. Thanks for the replies.
S.K.

 

[armorer951]

You might also check the integrity of the firing pin bushing in the breechface. (no burrs, flush with the breechface, etc.)

 

[sdk]

Yes, I've looked there and the bushing is flush. Thanks.
S.K.

 

[Tom S.]

Got me stumped. I'll have think on this one for a while.

 

[one eye joe]

I THINK THAT THE FACT THAT YOU HAVE AN UNFIRED ROUND WITH SCRAPES ON THE HEAD, IS A VERY SIGNIFICANT CLUE TO WHAT THE PROBLEM IS.....

IT IS MY UNDERSTANDING THAT THE INERTIA RESULTING FROM FIRING A REVOLVER, WOULD BE DRIVING AMMO, IN THE CHAMBERS, IN THE DIRECTION OF THE MUZZLE---NOT TO THE REAR. THAT IS WHAT CAUSES ROUNDS IN LIGHT WEIGHT, BIG BORE REVOLVERS, TO "JUMP CRIMP".......

WHY THESE .22 CAL ROUNDS WOULD BE FORCED BACKWARD, IS A MYSTERY TO ME---BUT IT APPEARS TO BE AT THE HEART OF THE PROBLEM......

 

[sdk]

If I point the revolver upward with the cylinder open, unfired rounds will fall out without pushing the ejector pin. It's understandable how they can move back during normal firing. Thanks for the reply.