B/C Gap
- Thread starter Hylander
- Start date
jaguarxk120
New member
My new Cattleman 45 is .004, that's with a empty case in the chamber lined up with the barrel.
I have a older (21 yrs. old) Cattleman at the gunsmith to have the barrel cylinder gap reset, it was .012 gap.
I have a older (21 yrs. old) Cattleman at the gunsmith to have the barrel cylinder gap reset, it was .012 gap.
Pathfinder45
New member
I once had a very old and weathered Colt SAA 45 that had excessive and uneven B/C gap; the worst I've ever seen. But I'll be darned if it didn't shoot real well.
ShootistPRS
New member
Measuring the cylinder gap requires the a case is in the firing position. If you check the gap without the case there it will and should be larger.
A canted front sight would be a bigger issue for me. For a LONG time .006" was considered a good standard and +/- .002" was considered tolerable if the gun shot well. And for a LONG time, the smaller gap was less desirable, as it fouled faster when all the ammo was black powder.
Get the sight straight, then see how it shoots, and don't freak on .008" gap, if it shoots well.
Get the sight straight, then see how it shoots, and don't freak on .008" gap, if it shoots well.
I believe that Kuhnhausen says that 0.006" is right for jacketed bullets and 0.008" is right for lubed lead bullets.
That's measured with the hammer back, as I recall.
Sounds like 0.008" would be ideal for a revolver when the manufacturer doesn't know for certain what type of ammo the buyer will use.
That's measured with the hammer back, as I recall.
Sounds like 0.008" would be ideal for a revolver when the manufacturer doesn't know for certain what type of ammo the buyer will use.
Driftwood Johnson
New member
Howdy
Yes, Kuhnhausen says that .006 is correct for jacketed bullets and .008 is correct for lubed leaded bullets.
However there is a little bit more to it than that. The correct way to measure barrel/cylinder gap is with the cylinder shoved forward. If there is any endshake (forward and backwards slop) endshake will mask the true b/c gap. That's why you make sure the cylinder is shoved all the way forward before running your shim stock through. Don't allow the shim stock to shove the cylinder backwards taking up the endshake. In theory there should be zero endshake, but that is not always true, a couple of thousandths of endshake is common.
For what it's worth, I have lots and lots of old revolvers. Some of them have gaps much larger than .008. None of them suffers much from accuracy that I can detect. When I buy an old revolver, I don't bring feeler gauges with me, I just eyeball the gap. I certainly would not sweat a gap of .007 or .008.
However I once owned a Cimarron Cattlman with a canted front sight, and I would not put up with that in a new gun.
Yes, Kuhnhausen says that .006 is correct for jacketed bullets and .008 is correct for lubed leaded bullets.
However there is a little bit more to it than that. The correct way to measure barrel/cylinder gap is with the cylinder shoved forward. If there is any endshake (forward and backwards slop) endshake will mask the true b/c gap. That's why you make sure the cylinder is shoved all the way forward before running your shim stock through. Don't allow the shim stock to shove the cylinder backwards taking up the endshake. In theory there should be zero endshake, but that is not always true, a couple of thousandths of endshake is common.
For what it's worth, I have lots and lots of old revolvers. Some of them have gaps much larger than .008. None of them suffers much from accuracy that I can detect. When I buy an old revolver, I don't bring feeler gauges with me, I just eyeball the gap. I certainly would not sweat a gap of .007 or .008.
However I once owned a Cimarron Cattlman with a canted front sight, and I would not put up with that in a new gun.
jackmoser65
New member
The improper application of information gleaned from magazine articles has people worried over all sorts of things, getting out their expensive pin gauges and fretting over barrel cylinder gaps before they ever fire the first shot. Here's a not so subtle hint, shoot it first and determine if there actually is a problem before worrying about fixing it. It's not a Freedom Arms, just shoot the danged thing. 
Driftwood Johnson
New member
He said the front sight is also canted. That is a problem. As I said earlier I used to have an Uberti Cattleman with a canted front sight. I bought it used and did not notice until later that the front sight was leaning to one side. It had not been torqued in properly.
So even though the gap is not a problem, the front sight should be straight up and down. If I bought a brand new revolver I would expect the sight to be properly straight up and down.
Now I know to always make sure the front sight is straight up and down on a SAA type replica.
So even though the gap is not a problem, the front sight should be straight up and down. If I bought a brand new revolver I would expect the sight to be properly straight up and down.
Now I know to always make sure the front sight is straight up and down on a SAA type replica.
Bamashooter
New member
Isnt there a certain way to check the cylinder gap? For some reason Im thinking with the revolver cocked you pull and hold the trigger and check it then. Im not a huge revolver guy so Im not sure.
Driftwood Johnson
New member
See my answer in post #14 above. With a single action revolver, it does not matter if the hammer is cocked or down, but it is more convenient to measure the b/c gap with the hammer down. If there is endshake present, the cylinder will slide back and forth anyway. The cylinder should be shoved as far forward as possible to measure the b/c gap.