Cylinder Clearance

M

makarov

New member
What should the clearance be between the cylinder and barrel on a revolver? I was cleaning my new (old) Ruger Security Six and although the lockup is tight there seems to be a pretty big gap between the cylinder and barrel. What would be normal for a revolver like this?

- Thanks
 
Well I just measured it with my valve adjusting feeler guages. .009 will not go through .007 will easily and .008 is a snug fit. This still seems like a large gap, but is this acceptable for this gun? What do most revolvers have for gap?

-Thanks.
 
Sounds like you are running around 7 1/2 thousanths. Not what you could call tight but certainly within tolerance. Gets past nine thou then you might consider doin something about it. Not a quick fix tho, probably mean turning the barrel in a full turn and then trimming and re finishing the cone.

Did you check the clearance of all chambers?

Sam.....my favorite 9mm is the 9X32R
 
Just because you measure 7 thous doesn't meat that is correct. You need to support the back of the cylinder, otherwise you are measuring endshake also.

-CAL
 
With the cylinder fully to the rear, the barrel-cylinder gap should run .006-007. A little more (008-009) won't hurt too much. Over that is definitely excessive.

If you go lower, you will not have problems until the gun warms up, when the cylinder might bind.

The uniformity of the gap is important also. If the back of the barrel or the front of the cylinder is not cut straight, you may experience inaccuracy.

Jim
 
I have made new barrels for North American Arms mini revolvers out of surplus barrel liners. One has the option, when fitting a barrel to a revolver, to make the gap small. If I cock the gun and then tighten the barrel, there is no cylinder gap.

How big must the cylinder gap be to reliably use the revolver? .005~.010" it turns out. It takes a big gap to be reliable.
 
Hi, Clark,

With the mini revolvers, the gap can be fairly small, since it would be unlikely that they would be fired long enough to heat up and they need every ounce of pressure to make up for the short barrel and small caliber. I think I would go less than the .006 I stated as optimum above and go down to .003-.004. If you went that small on a single action to be used in Cowboy Action shooting, it would heat and bind pretty quickly.

Jim

Jim
 
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