Cylinder Gap ?

[Hylander]

New Ruger Vaquero .45 colt.
What is the norm ?
I have two brand new SS Vaquero's at work, one measures a tight .007 and the other a loose .006
The blued model measures .004
I will be shooting mostly cast.

 

[contender]

Nominal is about .006.

 

[Hylander]

Nominal is about .006.

Should I hold out for something with a tighter tolerance ?
I want the best accuracy with cast loads

 

[rugerguy]

gap will affect "pressures" (velocity) not so much the accuracy...too close, with build up, will crud and rub,,,,,, too far , spit and blow by, drop in pressures, that is one of the big differences in a revolver (gap) and a pistol, auto or bolt, closed breach...........and NO the average person would have a hard time telling or measuring the differences........

but yes , as Ty said the .006" is nominal, if you recall back to the days of the Dan Wesson, and their interchangible barrels & shrouds, they came with a .006" feeler gage

 

[Hylander]

Out of curiosity, What does some of your guys Rugers measure ?

 

[Chuck 100 yd]

I have only measured a couple of mine but they both ran between 4 and 6 thou.
That is on vaquero .45's. On all the rest if I eyeball it and it looks good, I never give it another thought. Anything beyond .008 would be cause for concern with me. Though not a deal breaker for a CAS shooter.

 

[Hylander]

We have a Blued model that measures under .006
Checking with Calipers the Throats measure .451 and the cylinders .481
How do these measurements sound ?

 

[WOB]

For shooting ordinary cast lead bullets, .008" cylinder gap is better since it allows the normal build-up of lead and bullet lube on the face of the cylinder without dragging excessively on the barrel.

WOB

 

[Hylander]

For shooting ordinary cast lead bullets, .008" cylinder gap is better since it allows the normal build-up of lead and bullet lube on the face of the cylinder without dragging excessively on the barrel.

WOB

What about excessive blow by ? or lead spitting ?

 

[David Bradshaw]

Hylander.... consider cylinder gap the necessary evil that allows the cylinder to spin. "Evil" as a euphemism for pressure leak and velocity loss. However, the gap does not degrade accuracy. The old standard is .006-inch, plus or minus. When cylinder face is square to cylinder axis, and there is no endshake, the revolver will function with .001-inch gap. Cylinder gap cannot be set tighter than endshake. Various conditions cause leading, and they may be gun related, bullet related, or both. Major causes of leading include chamber-to-bore misalignment, rough or crooked forcing cone, and rough or undersize chamber exits. These conditions along with bad timing and advanced forcing cone erosion contribute to spitting, the sideblast of bullet and powder particles. Bullet material can jam a tight gap, and the two major causes of this cylinder lockup are 1) timing and 2) rough chamber exits or forcing cone.

As one example of free rotation with tight cylinder gap, my Blackhawk .357 Maximum will not accept a .0015-inch feeler and has never hung up.

Of itself a large gap doesn't hurt accuracy, as my nickel M-29 8-3/8" with .010-inch gap proves. It is a 2" revolver @ 100 yards.

I don't like large gaps, but accept it without thought on performers, such as the M-29 above.
David Bradshaw

 

[REB]

I did some experimentation years ago with my Dan Wesson that I can set the gap on. I went from almost touching out to .010 and didn't see any difference in accuracy or spitting, If I remember correctly I did see a very small change in velocity. I did have some crono data but I cant seem to find it.

I had problems with a SP101 that came from the factory with a .002 gap. Shooting some of my rather dirty hand loads it would start to bind up rather quickly. It went back to the factory because I didn't have the tools at the time to cut it back and recut the forcing cone.