how to tighen lockup?


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texas bulldog
May 16, 2007, 02:44 PM
so...maybe a dumb question...

is there anything you can do short of ordering a new cylinder to improve the lockup on a particular revolver? if it has just a little shake...not bad, but could be tighter...do you just have to live with it, sell it, or trade it? any other options? will the company fix it? if so...how much would they likely charge? and what if it's a model they no longer offer?

just curious. i look forward to informed responses. thanks!

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Owen
May 16, 2007, 02:49 PM
are you talking about end shake (front to back) or the cylinder rotating left and right?

Old Fuff
May 16, 2007, 03:34 PM
Owen is right, rotational or back & forth play? Also, what make and model of revolver? There is no one answer that covers all makes and models on the market.

texas bulldog
May 16, 2007, 04:18 PM
sorry.

rotation, not end shake. and it's a smith.

dfariswheel
May 16, 2007, 05:17 PM
Your S&W MUST have some rotational play in the cylinder in order to work right.

The only revolvers to lock up tightly are the older Colt actions like the Python.
Colt's famous "Bank vault" lockup forces the cylinder into perfect alignment with the bore when the trigger is pulled and tightly locks it there.

Since the chamber is perfectly aligned with the bore, the bullet enters the bore centered and this eliminates bullet distortion. Since the bullet isn't distorted by hitting the barrels forcing cone, accuracy is better.
This is why the older Colt DA revolvers were famous for their superior accuracy.

The down side of this system is, the action must be in perfect adjustment or it simply doesn't work properly.
Since this type of action is much more difficult to build and requires hand fitting and adjustments, the gun is much more expensive to build.

S&W, Ruger, Dan Wesson, Taurus, and all other modern DA revolvers are designed to leave the cylinder loose at the moment of ignition.
This allows the bullet to force the cylinder into alignment with the bore.

The advantage of this system is, it's much cheaper to build since it requires little hand fitting, and even if it gets out of adjustment, the action will still work well.
The down side is, since the bullet never enters the bore perfectly centered and hits the forcing cone off-center, the bullet is distorted and accuracy isn't as good as it could be.

So, your S&W is working properly. There is no factory spec for how MUCH rotational play there can be.
The factory spec is how the revolver shoots and whether it's spitting bullet metal.
If accuracy is good, and it's not spitting bullet metal, it's in proper adjustment.

texas bulldog
May 16, 2007, 05:57 PM
hmm...that's interesting, dfariswheel.

i hadn't heard that before. it seems a little contrary to some other things i've heard, but i can buy it. anyone care to second this opinion?

i will say the colts i've handled lock up crazy tight [a beautiful thing!]. but even ruger seems to lock up a bit tighter than most of the used smiths i've handled. your posts seems to imply no significant difference between them. any comment on that?

dfariswheel
May 16, 2007, 06:46 PM
A used gun WILL get looser, but S&W has no standard for how loose before it needs repair.

As I said, the standard is: How accurate, and does it spit bullet metal.
However, common sense says that a cylinder that's WAY loose should be tightened up by fitting a new locking bolt, or in extreme cases, a new cylinder.

Owen
May 16, 2007, 06:56 PM
I don't know about the cylinder on a Smith, etc self aligning. It seems like the cylinder is awful heavy, and the time frame is awful short.

Hawk
May 16, 2007, 08:33 PM
A little knowledge is a dangerous thing, in my case.

I'd stumbled across a 57-3 and a 640 that were considerably tighter (rotationally) than a 686-6 that my dealer had. He kept on about the 686 was "normal".

Turns out he was right. I've got a really sweet "normal" 686 and a couple of "over-tight but sure doesn't hurt" Smiths.

As noted in the Jim March thread, rotational "looseness" is a relative thing and I had the (mis?)fortune of my first used purchases being uncommonly tight.

I'll figure this stuff out eventually.

Wild horses, hand grenades and kerosene couldn't get that 686 away from me now and I'd already referred to it as a "castonet" elsewhere.

rxraptor02
May 16, 2007, 08:43 PM
Thanks for posting this everyone,

I have a smith 66-7 that has the rotational play as well. I know know it is normal.

Old Fuff
May 16, 2007, 09:33 PM
Texas Bulldog:

Dfariswheel knows his Colt's, and his description of how the older models locked up was dead-on. However the system, as he pointed out, required careful hand fitting - which became costly - and over time that "careful fitting” became less and less. Ultimately Colt was forced to go to a newer design, which locked up in much the same way that Smith & Wesson's and Rugers did, and in my experience Colt's accuracy didn't drop off very much, if any. Also a little wear on the older Colt's hand would result in as much rotational movement as you see in a correctly fitted up S&W or Ruger.


To reduce rotational play Smith & Wesson's depend on a more precise fit between the cylinder stop and the notches in the cylinder. Also for the best result they need to have zero play between the yoke and frame. When this is the case the little rotational play that remains seems to not be consequential. However if the cylinder notches become peened out, or looseness between the yoke and frame develop, accuracy can suffer.

Smith & Wesson armorers address excessive rotational movement a number of ways. They may carefully peen metal back into the notches, or in extreme cases replace the cylinder. In addition they might install a thicker cylinder stop to take out some of the play. Cylinder yokes can be adjusted to eliminate movement between that part and the frame. Last but not least, absolute "no movement" is not necessary to get acceptable accuracy, and if each chamber is not concentric with the bore when the cylinder is locked with no rotational play, the result will be counterproductive when it comes to accuracy, as the bullet will always be shaved on one side.

wally
May 16, 2007, 09:42 PM
I heard claims that reaming the forcing cone deeper to make a shallower angle helps too. I've never had it done so I can't say. Brownells sells the tool kits to do it.

--wally.

Hawk
May 16, 2007, 09:48 PM
Ultimately Colt was forced to go to a newer design, which locked up in much the same way that Smith & Wesson's and Rugers did, and in my experience Colt's accuracy didn't drop off very much, if any. Also a little wear on the older Colt's hand would result in as much rotational movement as you see in a correctly fitted up S&W or Ruger.

Out of curiosity, where would my Dick's Special land in this universe? So far as I can tell, its only connection to a Python is the color of the box, and I'm not sure about that. It is "relatively tight" though.

Tyro
May 16, 2007, 10:07 PM
I heard claims that reaming the forcing cone deeper to make a shallower angle helps too. I've never had it done so I can't say. Brownells sells the tool kits to do it.

That sounds like Taylor throating.

http://www.alphaprecisioninc.com/revolver/default.htm

Old Fuff
May 16, 2007, 10:07 PM
Hawk:

Da.... :evil: :evil:

Your Detective Special is absolute junk, and the Old Fuff is the Designated Junk Collector (DJC).

Seriously, it is a scaled down Python so far as the lockwork's concerned. The design goes back to around 1907. Correctly fitted up it can't be beat by anything around the same size. Larger revolvers, yes - smaller ones, no.

Hawk
May 16, 2007, 10:20 PM
I wish I'd discovered revolvers earlier.

Old Fuff
May 16, 2007, 11:40 PM
Well you can make up for lost time... :evil: ;)

gezzer
May 17, 2007, 01:07 AM
Bottom line, how does it shoot? Good groups who cares?

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