Barrel Cylinder Gap is Too Large

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The Bolt Man

Bearcat
Joined
Aug 7, 2011
Messages
3
Location
Southern Minnesota
I have a Ruger Security Six with a 6" barrel. The barrel cylinder gap measures .007" when a gaap of .003" would be much more desirable.

What can be done to tighten up this gap?
 

Hondo44

Hawkeye
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Apr 3, 2009
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People's Republik of California
I don't think Ruger would correct it on their dime as it's within a reasonable tolerance. But a phone call to them might be worth it, you never know and they have great service.

The only corrective measure is to turn the barrel in another full revolution after relieving the shoulder on a lathe, then resetting the gap and rethroating the barrel. Probably $200 worth of work at least for a very minor issue if the gun functions properly as is.

Plan B is find another gun with a more acceptable gap to you and sell it.
 

Driftwood Johnson

Blackhawk
Joined
Sep 25, 2007
Messages
699
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Land of the Pilgrims
Howdy

I'm curious why you think .007 is too much of a gap. I have many, many revolvers, most of them have gaps between .005 and .008. They all shoot just fine. I do have a few with gaps as small as .003, but I don't really see any problem with a gap a little bit larger. As a matter of fact I have one antique S&W, made in 1881, that has a gap around .012, because the frame was stretched by shooting too many Smokeless rounds in it. I was a bit concerned when I saw how large the gap is, but it shoots just fine too.

Hondo44 is correct. The standard way to tighten up the gap is to turn the barrel in one more thread. Doing this requires relieving the shoulder by the amount of one thread, so that the barrel can be turned in. Then, the barrel is trimmed back the amount needed to get the desired gap. I doubt Ruger will do it for you, you will have to find a gunsmith to do it, and frankly, I don't see the need.

P.S. Don't forget, the proper way to measure the gap is with the cylinder pushed as far as possible to the front. If there is any endshake (front to back play of the cylinder) measuring the gap with the cylinder pushed back will give an erroneous reading of barrel/cylinder gap.
 

Acorn

Buckeye
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North Huntingdon Pa.
I'm happy with a .007 gap. I don't think there is much differrence in velocity, and too tight of a gap could cause binding if excess lead and powder residue were to build up.
 
Joined
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Pennsylvania
Just to be sure we're clear on measurement of cylinder to barrel gap: push cylinder forward to measure minimum clearance (.003" min spec) and push cylinder back to measure maximum clearance (.008" is listed as max spec). Also, measure from both sides of frame.

I have read that the six series typically came from factory with .004" to .006" measurements.

I have had problems when I've had revolvers set to .003", and I've needed it opened up a bit. I personally wouldn't worry about 0.007", as fixing it is rather expensive and involved.
 

flatgate

Hawkeye
Joined
Jun 18, 2001
Messages
6,784
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Star Valley, WY
My F-A's have B/C gaps in the 0.001"-0.002" range. Never a problem no matter how many times I've fired them w/o cleaning.

flatgate
 
Joined
Jun 19, 2009
Messages
1,443
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I have similar experience with my FA single actions, and in fact I just had a Ruger Blackhawk set up with minimum clearance and it measures a little under .002 - and it works fine so far.

My problem with the .003" clearance was on a double action Security Six .357 mag. I had problems when shooting rapid fire exercises and the cylinder got hot from firing. Just thermal expansion will cause the gap to close by .002" or so if I recall correctly.
 

TheDude

Single-Sixer
Joined
Dec 13, 2008
Messages
441
Location
Selah, WA
If the gun shoots fine, I cant imagine why on earth you would care about the cylinder gap. Shoot the hell out of it and send back to Ruger if you have any actual issues with it. I've only ever had to send one revolver back to Ruger in over 25 years of shooting them. Enjoy.
 

k22fan

Blackhawk
Joined
Apr 22, 2010
Messages
713
Over in S&W land b-c gap tolerances are said to be .004" minimum & .010" maximum. Since I'm primarily a DA shooter, I prefer b-c gaps to not be under .005" on DA revolvers because with tighter gaps a smidgen of leading or unburnt powder can add unpredictable drag to the DA pull. That drag would go unnoticed thumb cocking so teeny weenie gaps on SAs are fine with me. But for DA revolvers, because, even though our best developed cast bullet hand loads don't lead, not all the ammo we assemble turns out to be ideal and factory cartridges with swaged lead bullets ordinarily lead some. I think shooters focus on b-c gaps too much simply because they are so easy to measure, and I've found gaps up to .010" make no noticeable difference.
 
A

Anonymous

I've always understood B/C gaps were measured with cylinder pulled back????

Anyhow, I sent my Single-Six back to Ruger because it was spitting out of the sides. Gander Mtn. smith said gap was .011", Gander returned it for me. Ruger tech on phone later said Ruger's standard was .005-.010, but most turn out as .005-.007. I believe he meant all Rugers, not just the S-S.

Gun was returned (9 days) with invoice marked that it was rebarreled, with new pawl and frame screws, so they apparently thought timing was off, too.The gap measures just over .004 (both cylinders) now, my Bearcats are both about .005.
 

Bucks Owin

Hunter
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Mar 22, 2004
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3,196
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51st state of Jefferson
flatgate said:
My F-A's have B/C gaps in the 0.001"-0.002" range. Never a problem no matter how many times I've fired them w/o cleaning.

flatgate

10X Carl, not as much space for the powder crud to gather and gum things up IMHO....And according to Linebaugh, as much as 100 fps can be achieved with no other change than tightening up a fat B/C gap with his kind of loads in a .45LC... :wink:

John Linebaugh:

"If a particular gun showed sluggish signs we went from a .452 dia slug to a .454 thus creating more resistance, and better seal in the throats of the cylinder. We soon learned that TOLERANCES were very important. We started with setting back the barrels a thread and closing the barrel/cylinder gap to under .002 instead of the common factory gap of .006 plus. This alone can boost velocity over 100 fps without changing the load. We next went to smaller chambers and .454 chamber throats. This combination with a proper size .451 barrel and tight .002 cylinder gap made the .45 Colt more than we could ever hope for".
 

Bucks Owin

Hunter
Joined
Mar 22, 2004
Messages
3,196
Location
51st state of Jefferson
RonT said:
You don't want the gap to be too tight inorder to avoid binding when the gun heats up.

I haven't ever heard of a heat binding problem with a tightly fitted Freedom Arms revolver... (Or any other tightly built custom) :? Have you?

(And some of FA's calibers burn a LOT of powder with each shot! :shock: )
 

k22fan

Blackhawk
Joined
Apr 22, 2010
Messages
713
I doubt you could get a revolver hot enough to cause enough expansion to bind it up at the B-C gap. If anyone could, it would be S&W's professional show off faster blaster, Jerry Miculek. Even though he holds the weight of his revolver by its cylinder in his off hand while he tosses in the next moon clip with his strong hand, he's never shown any sign of his cylinder being uncomfortably hot.
 
Joined
Jun 19, 2009
Messages
1,443
Location
Pennsylvania
I was doing some looking at some Dan Wesson stuff and found this in the large model manual:

Insert barrel/cylinder gauge in place between face of cylinder and rear of barrel to determine if proper gap exists. You should feel pressure
against the gauge. but it should be possible to move gauge side to side. If proper gap is maintained between barrel and cylinder, proceed to
loading instructions. If gap is tight or excessive, proceed to barrel changing instructions and adjust barrel cylinder gap accordingly. The
proper gap for the .357 Maximum revolver is .002". For all other large frame and SuperMag revolvers the gap is .006".

I just found it interesting that the spec for the .357 max is so much tighter than the other chamberings.
 

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