Help me understand lockup.

[TheBigFellow]

Howdy! New S&W owner here who is a little confused.

Just recently I purchased a Model 64 trade in from J&G Sales. Not to long ago I inherited my grandfathers pre Model 10 from his time on the force and found myself completely smitten for K frames, and while I was (am) in love I didn't want to expose my newly acquired heirloom to any unnecessary abuse. Thus, me getting the 64.

Here's the issue. From my understanding, a revolver is in full lockup when the hammer is down and the trigger is held to the rear. On my pre-M10, there is a significant difference in rotational cylinder play between rest and lockup. On my 64 however, there is very little difference at all between rest and lockup.

The play is not super bad; in fact, I went to a S&W warranty center here in Wisconsin to see if I could get her tuned up and they told me nothing need be done, that it was fine. That alone would qualm my worry if it were not for my grandfather's gun and the way it locks up.

Do you think my 64 might have an issue, or is the only issue me over thinking this?

 

[TheBigFellow]

A couple other bits of info I should have included.

Mine is a 64-6, so MIM parts but no IL. It's been rendered DAO.

I HAVE fired some 150 rounds or so without any lead spitting or any buildup or noticeable wear on the forcing cone.

 

[adweisbe]

Some guns are tighter then others. S&Ws in general are designed to work with some rotational play unlike a Colt which should be locked up tight. The real question is how does it shoot?

 

[M29since14]

Here's the issue. From my understanding, a revolver is in full lockup when the hammer is down and the trigger is held to the rear. On my pre-M10, there is a significant difference in rotational cylinder play between rest and lockup. On my 64 however, there is very little difference at all between rest and lockup.

The play is not super bad...

Do you think my 64 might have an issue, or is the only issue me over thinking this?

If both guns are performing normally, don't worry about the differences between them.

In general, with a new-to-me gun, I mainly look at timing and endshake. These two things seem to be the ones that most commonly need attention, and are easily detected. Are both of your guns OK in these areas?

Without having tools, knowledge, and spare parts, nitpicking on a gun that is working normally is just causing yourself aggravation. You can imagine it would be nearly impossible to make two S&W revolvers that every detail of their fitting was identical.

 

[OKFC05]

I went to a S&W warranty center here in Wisconsin to see if I could get her tuned up and they told me nothing need be done, that it was fine

About the dumbest thing you could do is start screwing with a "fine" vintage S&W revolver.
Novices often obsess about a little wiggle in the cylinder and the turn line on the cylinder, neither of which need fixing.

By the way, a S&W revolver with "perfect" lockup may not shoot as well as one with a little wiggle, which can allow the bullet to center in the barrel.

 

[n4zov]

About the dumbest thing you could do is start screwing with a "fine" vintage S&W revolver.
Novices often obsess about a little wiggle in the cylinder and the turn line on the cylinder, neither of which need fixing.

By the way, a S&W revolver with "perfect" lockup may not shoot as well as one with a little wiggle, which can allow the bullet to center in the barrel.

Good advice! I have an old cut-down M1917 with a lot of cylinder movement, but the gun will deliver one hole groups at 15 yards all day long. The temptation to "fix" it is great, but I just keep thinking of how great it shoots. If it ain't broke........well, you know the rest.

 

[TheBigFellow]

Thanks for the reply's.

There is little to no endshake and the timing is alright. Accuracy is good to. So yeah, it seems I'm obsessing over nothing.

 

[brokenprism]

I, for one, wouldn't mind that definition of lockup. I have speculated whether it meant the condition of the gun 'at rest,' or the gun with the hammer back. Or is that (to borrow a term from semi-autos) 'in battery'?

 

[scooter123]

Brokenprism, the definition of "lockup" in a revolver means that the trigger is pulled fully to the rear with the hammer down.

As for cylinder play, IMO I would consider returning any S&W that didn't have some play in the cylinder at lockup. Because if there isn't some play in the cylinder it will beat up the cylinder stop if the notches aren't cut absolutely perfectly for the fitup of the cylinder to the barrel. It may also indicate an issue with a poorly fitted crane or bent ejector rod.

Bottomline, these are Combat Revolvers and they need some play in order to function well either when freshly cleaned or crudded up with a lax maintenance interval. IF S&W said there isn't anything wrong with your model 64, there isn't anything wrong with your model 64 and you should shoot the snot out of it.

 

[500 Magnum Nut]

As long as the cylinder stop snaps into each cylinder notch before the firing pin strikes the primer, your lock up is OK.

There are finer ways of measuring cylinder/barrel alignment but the above will keep you and your friends safe at the shooting line.

 

[dant]

good answers above and bottom line is its the diffence between "new & old" ,new production versus older production ( manufacturing tolerances??), then there is final "fit and finish" ( the build) and then add in wear (use) I'd say yours are just fine, as said above, "how does it shoot....?"

 

[TheBigFellow]

To be clear, the place I brought my pistol to have it checked over is actually a Gander Mountain that works as a warranty center for S&W; although the gunsmiths there did seem extremely knowledgeable.

What's kinda weird about my gun is that while lockup and rest exhibit similar levels of rotational play in the cylinder, the last moment of pulling the trigger BEFORE the hammer falls seems to lockup the revolver, at least more than at standard lockup.

Anyway, I'll go on a limb and take the advice given here; if it ain't broke, don't fix it. And she does shoot well as is.

I do have one other question if ya'll don't mind. When I DO start to experiences lead splitting, how damaging is this to the gun itself?

 

[dant]

leading splatter, (blow by) may NOT be the gun itself,but the ammo in use....more harmful to the user and folks standing nearby (next to you on the firing line) you can check by putting a large piece of cardboard, like a white one they used to put in 'new shirt' and make an arch out of it and place it over and cover BOTH sides of the revolver,(tape it to the bench or have someone else hole it in place......the splatter will show up on this cardboard (seen guys use white ,linen cloth, but seen them catch fire also???? again, may only be the ammo , or just a GOOD cleaning of the forcing cone, barrel .............'if it leads up, ( build up on the top strap or the face of the cylinder, , if you're 'gap'' is too close, may cause binding between the cylinder and the breach of the barrel................I would NOT worry about it..................you are going to get "gases' escaping out the 'gap' on ANY revolver...............

 

[tomcatt51]

What's kinda weird about my gun is that while lockup and rest exhibit similar levels of rotational play in the cylinder, the last moment of pulling the trigger BEFORE the hammer falls seems to lockup the revolver, at least more than at standard lockup.

I do have one other question if ya'll don't mind. When I DO start to experiences lead splitting, how damaging is this to the gun itself?

Being slightly tighter "the last moment of pulling the trigger BEFORE the hammer falls" usually means it has a slightly thicker than necessary hand.

All revolvers spit from the barrel cylinder gap, gas and powder particles more often than lead or jacket material. I have shot my 625 (SA) with the cylinder NOT locked, like it wasn't completey carrying up (which it wasn't if shot slowly DA which made me curious). The world didn't end, it didn't noticeably shave lead, the groups just opened up about an inch and it did rotate the cylinder so the stop "dropped in" when fired.

 

[2hawk]

This should help...

I just found this, the "S&W Inspection Guide" by Cactus Tactical.*

For more information, log on to Combat proven tactical equipment, self defense gear, AR-15 accessories, tactical gear, shooting supplies


*Post edited for copyrighted material issue.

 

[Skeeziks]

Adjustable Rear Sight: This test will indicate if the sight is working properly.

Use a proper screwdriver and rotate the windage screw back and forth then the elevation screw up and down. Count clicks so you can return to the proper setting. The sight leaf should track and not bind. Grab the sight leaf and see if it has free play. None should be noted.
------------------------------------------------------------------------

My recently acquired 686-4 has a rear sight leaf with a LOT of free play!
What should I do?

 

[TheBigFellow]

Last Time!

OK, I swear to GOD this is my last post on the matter. I rigged up a crappy $70 camera and got a video of the play in action.

YouTube - M64.mov

Note that this gun is DAO, so to get to full lockup I need to dry fire.

Again I'd like to thank everyone for their responses and look forward to participating in this community!

 

[Ira Aten]

I don't know exactly where to go with this question, and this seems like a related issue for a model 36. I don't wish to hijack a thread, but can't find a specific thread for model 36 gunsmithing, and I am worried about my wife's model 36. As I am sure you guys know, the cylinder revolves counter-clockwise when shooting it, and the cylinder stop works to make it lock up, etc.
Here is the problem. The cylinder on this gun will turn clockwise quite easily by just turning the cylinder by hand clockwise.
Is the cylinder stop "beat up" and if I replace the cylinder stop, will it halt that issue?

 

[2hawk]

OK, I guess I'll give this a try...

First off, I am not a gunsmith. There are many more qualified than me on this forum to answer the questions above, but I'll offer my qualified opinion for the meantime.

Skeeziks, check to see if the nut on the opposite side of the windage screw is properly staked. If it *doesn't* turn when you adjust windage, you need to stake it. Directions on site replacement are in the FAQ tacked at the top, I think. It sounds like the windage screw might be broken or stripped, to tell the truth. You can get a replacement from Brownells.

Big Fellow, hard to tell from the video, but you may have a bit more than optimal rotational play. Some play is part of the design, allowing the projectile to "self center" when entering the forcing cone. If you are not experiencing spitting or accuracy issues, no reason to change anything. If you are having issues, you may need a new cylinder stop, and I would suggest sending the gun to the factory for that work. If you do send it to S&W, describe the problem as well as you can, and ask that timing and endshake be checked and corrected as needed.

Ira, you definitely have an issue that could prove unsafe. It sounds like you need a new cylinder stop, but the original might be usable with some re-fitting. I think there is some info on this in the FAQ as well.

For anyone with questions on the inner workings of your S&W revolvers, I think that the best investment you can make is a copy of Jerry Kuhnhausen's "S&W Shop Manual." Even if you never touch your gun with tools other than cleaning implements, it describes in detail how all the parts work together. A great reference if you think you might have an issue.

"The S&W Revolver: A Shop Manual" Book by Jerry Kuhnhausen - MidwayUSA

It's probably cheaper at Amazon, but at least Midway contributes to gun rights.

HTH