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S&W 610 and cylinder gap


Makicjf
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Howdy,

    Last summer my 610 returned to Smith as the trigger post had broken.  Many moons later, I received an email stating it needed timing correction, cylinder gap correction and the trigger post repaired.  The cost would be $185 ( I don't remember the exact figure). I had bought it used,  had no idea of the history, so paid the squeeze.  It came home about a month ago, I stuck the apex extended firing pin in it and stuck it on the rack.  I had it out yesterday, as I was going to set the  strain screw at minimum for Winchester primers.   I experienced every other round light strikes in DA with the full length screw sunk all the way on fully seated Winchester primers, TK 610 moonclips, starline 10 mm brass.   Another DA strike would not light the round, but a single action strike would.40 S&W and 10 mm will function with federal primers, but only with the strain screw buried.  Lacking a trigger gauge, I don't know the weight, but it is stout.   

   I do not have feeler gauges, but I'm wondering if the cylinder gap was set to minimum, thus increasing the headspace distance to the razors edge of function.   Might it be worth shimming the cylinder back a .002 to .004 and seeing if the light strike issue abates?     The pull is stout enough it should crack large rifle magnum primers, but will only pop deep seated federals.

Thanks!

Jason

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Factory S&W is .0006, any closer and bullet fowling will build up and stall your cylinder rotation.

 

We always used Federal Small Primers... if this doesn't  help work on your firing pin, dont shim the cylinder.

 

In the 80s we use to trim the cylinder short 1/2"+ and re-thread the barrel to .0004 to shoot more accurate PPC loads with 148 gr HBWC under 2.8 gr of Bullseye.

 

While we thought this was better, our scores never improved....

 

 

 

Edited by Bill Sahlberg
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I've always had good luck with the apex pin that is installed.  How can I improve pin reach?   I've also not yet bobbed the hammer.  Would removing the hammer spur make any appreciable difference in hammer velocity and pin impact speed?  I'd really prefer not to have a field carry/ hog gun be ammo sensitive or require federal primers.

I don't see any binding on the hammer and the internals are well polished.  

Upon reflection, it is possible I removed the factory pin, opened the Apex pin, then re-inserted the factory pin.  I'll  measure the pin in the box.

Thanks !

Jason

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With that hard of a mainspring setting, something else is going on. That setting should smash even CCI primers every time. Bobbing the hammer won't help until you figure out what the main problem is and get that corrected. There is something major blocking or slowing the hammer fall.

 

The shortest firing pin that will be reliable is .495. That is the longest factory pin I've seen. I like one in the .500 to .505 range. A full radius tip on the firing pin gives the lightest hammer strike possibility.

 

You want about .006 cylinder gap ideally, for lead or lead and jacketed. You can go down to .004 for jacketed only, but then have to keep a close eye on endshake. You want to have .005 to .010 space between the brass and the recoil shield for headspace. Check with feeler gages.

 

If you have a trigger stop, the trigger may not be going back far enough for the hammer to clear the rebound slide when the hammer is all the way down. If the hammer touches the rebound slide at all, it will act as a shock absorber (spring loaded) and dampen the hammer blow to the firing pin. You can check this by pulling the trigger, hold the hammer all the way against the frame, and see if the trigger has any front to back play. There should be at least a little bit of trigger movement with the hammer all the way down.

 

Check to make sure that the hammer isn't hitting the hammer block as it falls. You can remove the hammer block and see if the situation improves.

 

If you have shims on the sides of the hammer (or don't), the sideplate could be binding the movement of the hammer. See if the hammer can move freely with the sideplate tightened down and the mainspring disconnected.

Edited by Toolguy
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The hammer seems to move freely w/o the mainspring; and the trigger has a bit of travel with the hammer pulled to the frame.  I'm picking up feeler gauges today.  

Is it possible the double action arm is at the quivering edge of to short and the hammer is dropping to soon?  Visually the travel rearward in DA seems short compared to my other N frames.  How could I measure this?  The 610 is also the only hammer with a spur, and it often hits my hand.  Could that stop rearward travel?

Thanks!

Jason

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Check to see how far the firing pin sticks out with the hammer down. It should be about the thickness of a penny. You can check this with the cylinder open (pull back the thumblatch) and pull the trigger and hold it down. I'm wondering if there may be 2 firing pin springs in the firing pin hole?

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2 hours ago, Toolguy said:

Check to see how far the firing pin sticks out with the hammer down. It should be about the thickness of a penny. You can check this with the cylinder open (pull back the thumblatch) and pull the trigger and hold it down. I'm wondering if there may be 2 firing pin springs in the firing pin hole?

I had the same thought last night:  when measuring the pin I physically removed the FP spring and made certain there was only one spring.  I also swabbed out the fp channel really well.   There is only one FP Apex spring.  

    I'm wondering if I'm chasing a Red Herring of my own creation.  I've fired 40 S&W factory and S&B 10 mm factory and the primers are positively crushed and caved in.  The Federal reloads look the same.   My reloads with gold primers will just have a minor dent.  A second DA strike will not pop them, but a single action strike will.  Its possible I have:

1) a batch of ammo where for some inexplicable reason did not set the primers well

2) I managed to load large rifle primers into large pistol brass 

3) a worst case combination of all three.

 

If this evening allows me time, I'm going to string up some factory 40 on the flimsy, generic 10 mm moon clips, creating a stacked deck towards light strikes and cook of 30 or 36 rounds and see if they will light strike.  If I can't make a light strike occur, I'm going to assume  the 10 mm rounds I'm using are the culprit.  Ill get rid of them in single action.  

   I stopped at a local gun shop over lunch and the cylinder gap is generous at .0095 +/-.  I didn't have any moon clips to check the headspace, but I'll do that soon.

Thanks for all the help.

Jason

 

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18 hours ago, Toolguy said:

You're welcome, Jason. I hope you get it figured out. Please let us know how it ends up.

   I think I mixed up primers on a batch of 10mm last fall.

 

When the revo has the factory springs and factory strain screw sunk it consistently crushed:

S&B 180 grain JHP 10mm

Remington 165 grain BTJHP 40 S&W in flimsy 10 mm (non-TK) moon slips

 

Single action was required to break what I can only assume were large rifle primers in 10 mm cases . ( I shot them all)

 

I'm going to go forward and file a strain screw for Federal primers/ 40 S&W in the 10 mm clips.  This should give me sufficient latitude to break any federal primer in any possible combo of clips and ammo (  10 mm/40)  I'll keep the factory screw for factory loads.

I did bob the hammer, and the 610 is much more pleasant to shoot without the spur hitting my hand.

Thanks  for the help.

Jason

 

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2 hours ago, Makicjf said:

   I think I mixed up primers on a batch of 10mm last fall.

 

I would think that if you mixed up large rifle primers instead of large pistol primers, you would have had high primers on the loaded shells. The LR are the same dia. but are thicker than the LP ones. Right off I can't remember exactly but .010 to .015 is what I am thinking. Small rifle and small pistol are the same dimensions, but the small rifle have harder cups to handle the higher pressures that are found in rifles.

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2 hours ago, mchapman said:

I would think that if you mixed up large rifle primers instead of large pistol primers, you would have had high primers on the loaded shells. The LR are the same dia. but are thicker than the LP ones. Right off I can't remember exactly but .010 to .015 is what I am thinking. Small rifle and small pistol are the same dimensions, but the small rifle have harder cups to handle the higher pressures that are found in rifles.

Mark,

       you are correct, the large rifle primers are taller.  I'm just guessing why a bunch of ammo would light strike at full power.  The primers would explain the problem.  You are correct, though, I don't know if a large rifle primer would even allow the cylinder to rotate.

Jason

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2 hours ago, Makicjf said:

Mark,

       you are correct, the large rifle primers are taller.  I'm just guessing why a bunch of ammo would light strike at full power.  The primers would explain the problem.  You are correct, though, I don't know if a large rifle primer would even allow the cylinder to rotate.

Jason

I know that it can be frustrating, I am having issues with my 610 also.  Having light strikes, have to have a heavy trigger pull, but the cylinder also will lock up after a shot sometimes. I have tried different lengths of firing pins springs and checked endplay. I am real close to just boxing it up and sending it to Joe at MOJO to see if he can find what I am missing.

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6 hours ago, Sanzo said:

Mark, 

 

Have you tried different moonclips?

   Sanzo,

                  The only 2 moon clips I'm aware of for the 610 are the .035 thick from TK which I'm pretty certain are de facto Starline ( it looks cooler if I type it like this: *---) clips.  Starline 10 mm clicks in well and feels nice.  All my other 10mm brass are to tight for the .035 TK clips.  The old school fingered moon clips fit all of the 10mm brass, but fit strarline almost to lose for rapid, consistent reloads.  Ostensibly, with 10mm brass the brass itself should provide headspace on the case mouth.  I've actually  checked that all the brass will fire without the moon clips.   As far as I can tell, with 10 mm brass the clips only provide extraction and rapid refills.

 

I don't know why this is being underlined, so please ignore the unintentional emphasis .  Once again, technology kicks my butt.

 

  I was hoping to shoot my mixed 40 brass with a decent pull weight, but found that even with forcing the brass into the .035 clips, the pull had to be substantial for consistent ignition, even with Fed primers.   I gave up and set the trigger for 10 mm brass, and federal primers.  

   Sadly, the 610 has the least smooth and stiffest trigger  f all four of my N frames.  I polished them all the same, but none of the others are picky and are glass smooth an and around  5/ 3/4 - 6 lbs ( plenty light for me)  The 610 in order to break Fed primers  with properly headspaced 10 mm brass in stiff TK moon clips needs at least a 9-9.5 lbs trigger.     

 

If you know of other moon clips, I'd be glad to try them, but I've given up on 40 out of the 610.  It requires a sledge hammer to go off!

Maybe someone with more knowledge and skill could fix it, but my 625 is smoother, slicker, has less blast and throws a bigger bullet at much lower pressure.  So I'll just stick with 45 colt or 45 colt equivalent loads for pig ventilation.  Yes,  of all my " 4 bore" wheel guns, the 610 is by far my least favorite, and is almost as problematic as the long departed Ruger Redhawk in 45 Colt.  We got the Redhawk to work, after the new Bowen pin became available, but by then I had lost all faith in the Redhawk as a paper weight let alone for a packin' / self defense pistol.

 Do you know of other 610 moon clips?

Jason

Edited by Makicjf
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Jason,

I have a new 610 and using Ranch Products moon  clips  with CCI primers  and every brand of .40 cal  brass imaginable I have had zero failures of any kind.  The clips work great and in fact i am shooting so much that I bought a new Dillon with a bullet feeder to keep me in ammo. Hope you get it figured out.

John

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I’ll try not to take the underlining personal.   Freaking aggies 😉

 

ive been going through a long list of Greif with a 625 (model of 1989) I picked up.  Getting it to fire from single mode was easy. Everything else was awful.  Cylinder wouldn’t rotate well, Hand was binding in the slot, and while tk moonclips worked, they only worked it the logo was facing the cylinder. Bought some Wilson combat moons and it was even worse.  Couldn’t even close the cylinder.  I’m really funny about my brass and have a thing for sig sauer brass in my revos. Nothing worked
 

gave it to 357454 for a week and he brought it back Sunday with much cussing, swearing, and a “be glad I don’t charge by the hour”!  It’s definitely better, but I’m worried this will be my albatross gun.  I keep eyeing the 610 as it’s possible L6 replacement so it hurts me in the feels to hear both of you are having a hard time with them.  

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Don't judge the new production guns by my experience.  This is an old gun I bought used.

I'm also going to try the ranch product Moonies.  I have about 2k of 40 that I really don't want to chase.  If they allow the 610 to pew with 40 brass and a decent pull, I'll be thrilled!

Thank you, Gentleman!

Jason

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The Ranch Product moon clips are identical to the S&W 610 moon clips I already have.   It was certainly worth investigating!  I may just put the factory strain screw in the 610 and use it that way.  That gives me a bunch of options ( but a heavy trigger).  I may fiddle with the return spring.  I usually leave that heavy, as I like a snappy return, but reducing the TRS may buy me a bit of pull weight without sacrificing reliability.

Thanks!

Jason

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The best way to see what effect the rebound spring is having on your action is to take out the hammer and see what the trigger pull is with just the trigger and rebound slide and spring. The Wolff 11 pound is a bit over 2 pounds of actual trigger pull weight, up to the factory spring that is around 4 pounds, with the 12 to 15 pound springs somewhere in between. Though the springs are rated at several pounds of force, you get a big mechanical advantage on the spring with the lever arm of the trigger, so the actual pull weight in the gun is quite a bit less than just the spring force by direct measurement.

 

The quick, easy way to get the lightest trigger pull is to get the mainspring set to where there are no misfires, then find the lightest rebound spring that gives the trigger return feel you want. A set of Wolff rebound springs is a cheap investment. You should easily be able to get under 8 lb. reliable action with Federal primers. Most of mine that have factory parts are 6.5 to 7 lb. D/A. If not, there is probably something wrong with the gun that needs to be fixed. Every gun is an individual entity based on all the plus and minus tolerances of each part that makes up that gun, so no 2 actions will be exactly alike. They should be able to all be in the same general ballpark, though.

Edited by Toolguy
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2 hours ago, Toolguy said:

The best way to see what effect the rebound spring is having on your action is to take out the hammer and see what the trigger pull is with just the trigger and rebound slide and spring. The Wolff 11 pound is a bit over 2 pounds of actual trigger pull weight, up to the factory spring that is around 4 pounds, with the 12 to 15 pound springs somewhere in between. Though the springs are rated at several pounds of force, you get a big mechanical advantage on the spring with the lever arm of the trigger, so the actual pull weight in the gun is quite a bit less than just the spring force by direct measurement.

 

The quick, easy way to get the lightest trigger pull is to get the mainspring set to where there are no misfires, then find the lightest rebound spring that gives the trigger return feel you want. A set of Wolff rebound springs is a cheap investment. You should easily be able to get under 8 lb. reliable action with Federal primers. Most of mine that have factory parts are 6.5 to 7 lb. D/A. If not, there is probably something wrong with the gun that needs to be fixed. Every gun is an individual entity based on all the plus and minus tolerances of each part that makes up that gun, so no 2 actions will be exactly alike. They should be able to all be in the same general ballpark, though.

Thank You!  I'll give that a try!

Jason

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Does your gun have the firing pin on the hammer or the frame? In either case, you want the firing pin to stick out about the thickness of a dime with the hammer all the way down. If not, the firing pin may be too short. For frame mounted firing pins, the shortest reliable ones are .495 long, which is the longest factory ones I've seen. I prefer to have mine in the .500 to .505 length. Power Custom has the ones I like best.

 

For hammer mounted firing pins (hammer nose) if you need it longer you can order a new one of those from Power Custom or take off the original, grind back the face of the hammer on a belt or disc sander, and put the pin back on. The firing pin will extend out more by the same amount you took off the face of the hammer. Be sure to keep the original angle of the hammer face and don't take off more than .010. Once it's all back together, push the hammer all the way down and make sure you have a bit of play in the hammer nose when it sticks through the hammer nose bushing. If not, you will need to grind a little bit off the radiused parts of the nose to give some clearance so it's not hitting the bushing.                     www.powercustom.com

Edited by Toolguy
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