[Dr. Tad Hussein Winslow]

Just brought home a little Taurus 85 .38 spl I got in trade today - The gap looks too wide. Looks to be maybe 1/32nd to 3/64ths". :eek: More daylight than I'm used to seeing in my other revolvers. Use spark plug tool to measure? Or how? What should it be? Thanks.

[rcmodel]

Probably .008" max, but .004" - .006" is better.

Use a steel shim-stock type feeler guage, not a spark-plug guage.

rcmodel

[dfariswheel]

Each maker has their own standards as to the acceptable gap, and even those specs have changed over the years.

"In general", a gap of 0.005" is "perfect".
In practice, a minimum of 0.004" and a maximum of 0.008" is in spec.
Some makers will allow gaps as large as 0.010", OR EVEN MORE.

[Dr. Tad Hussein Winslow]

Ok, thanks. It's probably not nearly as much as it looks eyeballing it, but I'd guess it's more than 1/100th". I don't guess a set of spark plug gauge tools will go thin enough, will it? Special tool required - go to Brownell's? At what point is it *dangerous*?

[machinisttx]

Ok, thanks. It's probably not nearly as much as it looks eyeballing it, but I'd guess it's more than 1/100th"

.010" is in spec for Taurus IIRC.

Your local autoparts store or Sears should carry leaf type feeler gages. link to Sears feeler gage--click me (http://content.sears.com/shc/s/p_10153_12605_00940804000P?vName=Tools&cName=Mechanics+Tools&keyword=specialty)

[rcmodel]

.010" is in spec for Taurus IIRC.Yet another reason not to buy a Taurus.

rcmodel

[brickeyee]

http://www.mytoolstore.com/kd/kdfeel01.html

Less than $10

[rcmodel]

Any auto-parts store worth it's salt should have them locally.

Widely used to adjust the valves in motorcycles, lawn mowers, and hotrod car engines with adjustable tappets.

rcmodel

[Jim K]

Most folks tend to think that the smaller the gap the better. But if the gap is too small, the gun will stop working after a few rounds when the cylinder expands lengthwise from heat and binds against the barrel. I consider .006-007" to be ideal.

Jim

[Dr. Tad Hussein Winslow]

Thanks all. When would you say it's dangerous large? .015? .02?

[SeanSw]

.002" on my little used Security Six. It starts to gum up in as little as 6 shots. A gap of.005" on my S&W has never given me a hitch.

[Dr. Tad Hussein Winslow]

It's .008 or a "tight .009". I guess that means it's .009. Way smaller than I thought. High but within tolerance, I suppose.

$7 for a 32-blade feeler gauge should be money well spent.

My toolbox for examining guns at shows/pawn shops is growing:

-Bore light
-Regular flashlight
-Bore snakes
-Snips for cutting tip ties off actions
-Fjestad Blue Book
-Feeler gauge

Still, does anyone know the answer to my question?

When would you say it's dangerously large? .015? .02?

[rcmodel]

Yep!

Takes a highly trained & calibrated eyeball to eyeball thousandths!

rcmodel

[Jim K]

There really is no specific point at which the barrel-cylinder gap can be said to be "dangerous." If you shoot from a bench at arms' length, wear eye protection, and with no part of your body up beside the gap, a large gap could be tolerable, perhaps even unnoticed.

But if you are one of the folks who pull a revolver trigger with the middle finger and extend the index finger along the frame, even a tight gap may lead to severe pain.

Also, if you shoot on a range where there are other shooters beside you, they may express some concern about receiving the dubious benefits of a large gap. This usually comes in the form of a gentle reminder that if you fire one more shot, your gun may be seized and forcibly inserted into a tender portion of your posterior.

Jim