Is There a Standard Max Min Cylinder to Forcing Cone Clearance?

[Load Master]

I have a Ruger Super Blackhawk Hunter 44 Rem Mag Revolver and there is about .032 clearance between the cylinder and forcing cone. I've tried to find what the max/min value should be on the web, but haven't found it. Anyone know where I might find this dimension? I guess I could call Ruger.

 

[JohnKSa]

I suspect you're measuring it incorrectly, or expressing it in units other than inches. If you are measuring it properly and expressing the gap in inches, then there's a problem.

You'll see people argue about whether or not 0.010" is too large or not, but I don't think anyone is going to stand up and defend a 0.032" gap--that's huge.

Even if you're expressing it in centimeters, 0.032" would be about 0.013" which is still on the large side. I don't know that I would return a revolver for having a 0.013" gap, but I also certainly wouldn't consider it ideal, by any means.

 

[9mmepiphany]

I've always understood that 4 to 7 thousandths (.004" - .007") was considered "in-spec"

I think my competition 686 is set at .003"

Here's an old thread from the Ruger Forum about cylinder gap

 

[Alaskan Ironworker]

All of the 14 revolvers I own/owned measured between .005 and .009 and they all seemed to fire and function well. That includes smiths, rugers, and tauruses. I presume tighter is better assuming you clean the powder residue/lead/filth off the cylinder face regularly. My opinion is anything over .010 is excessive, and ill bet ruger would agree.

 

[JTown]

I suspect Load Master didn't add enough zeros to his dimension. Should be .0032 not .032. I like the clearance about .004

 

[MidRoad]

I have a Ruger Super Blackhawk Hunter 44 Rem Mag Revolver and there is about .032 clearance between the cylinder and forcing cone. I've tried to find what the max/min value should be on the web, but haven't found it. Anyone know where I might find this dimension? I guess I could call Ruger.
View attachment 793076

Little off topic, but what grips are those?

 

[243winxb]

about .032 clear

Type O , i hope. The photo makes it look that big. But photos can be deceiving.

Had a J.P. Sauer And Sohn, Hawes 44 magnum with a huge gap. Not something you could live with.
Produced concussion and a ball of fire, right in my face. Never fired it again. Sold it.

 

[Load Master]

UPDATE: There is a good reason to use feeler gauges in place of one's eyeballs! I originally posted this late last night and I found my calibrated eyeballs are not what they once were. Using a .005" feeler gauge, it passes easily, a .006" will pass but tightly, .007" will not go in. I expect with these numbers I am good to go.

I just picked this revolver up the other day. I've been going through it in detail and wanted to check it over before putting any rounds through it.

Thanks guys for the feedback.

 

[Load Master]

Little off topic, but what grips are those?

They are "Pachmayr Gripper Grips with Finger Grooves Ruger New Model Super Blackhawk Rubber Black".
LINK

 

[MidRoad]

Thanks, my dad was having a hard time finding grips for his Hunter . Most grips seem to be for the dragoon style. Those seem to fit pretty well.

 

[Driftwood Johnson]

Howdy

According to Jerry Kuhnhausen in The Ruger Single Action Revolvers Shop Manual, defacto barrel/cylinder gap of .004-.006 is standard for revolvers set up for jacketed bullets, and .008+ for revolvers set up for lubricated soft lead bullets.

In my own collection of revolvers, most of them fall between .005 and .008.

I have one antique Merwin Hulbert with a massive gap of about .015, if I recall correctly, due to its open top configuration. The frame has bent slightly over time. For what its worth, it shoots fine with my Black Powder loads.

 

[BSA1]

I have a pair of Ruger Vaqueros in 45 Colt that I have used for many years in CAS and CMAS. When I active I shot a lot and between work and reloading more ammo I would not clean my guns until winter. (With blanks used in CMAS I give them a quick wet patch through the barrel and chambers to kill any salts). I just gave them a few drops of CLP when they started to run sluggish.

The b/c gap on one of them measured .001 on one side and .003 on the other! I have a gunsmith open the b/c gap to .008 and recut the forcing cone for lead bullets on both of them. I like the larger b/c gap on my revolvers since I shoot mostly lead bullets and the lead builds up on the front of the cylinder. For reference .008 is about the thickness of a business card.

I demand a lot of reliability from my revolvers and will not accept excuses for the cylinder binding up from too tight of a b/c gap.

 

[Eddietruett]

Just had a long conversation with one of the best gunsmiths in the country concerning cylinder gap. He just did a barrel swap for me and set gap at .004 as he does on all normal swaps. The smaller the gap the more accurate but you have to be really really good to tell the difference. He built many competition guns in the day and most of the best shooters requested a gap from .002-.004. One of the problems you can encounter with a real small gap is the smallest bit of lead build up can bind the cylinder. I’ve been told that Smith used to consider anything over .008 to be out of spec but now anything under .012 is acceptable.

 

[gotboostvr]

I have a pair of Ruger Vaqueros in 45 Colt that I have used for many years in CAS and CMAS. When I active I shot a lot and between work and reloading more ammo I would not clean my guns until winter. (With blanks used in CMAS I give them a quick wet patch through the barrel and chambers to kill any salts). I just gave them a few drops of CLP when they started to run sluggish.

The b/c gap on one of them measured .001 on one side and .003 on the other! I have a gunsmith open the b/c gap to .008 and recut the forcing cone for lead bullets on both of them. I like the larger b/c gap on my revolvers since I shoot mostly lead bullets and the lead builds up on the front of the cylinder. For reference .008 is about the thickness of a business card.

I demand a lot of reliability from my revolvers and will not accept excuses for the cylinder binding up from too tight of a b/c gap.

Have you done any before/after chrono testing when adjusting the B/C gap?

 

[flightsimmer]

That's what I always liked about the Dan Wesson revolvers, you could set the gap to suit yourself.

I once upon a time loosened the gap to .010" and then narrowed it to .002 and you could tell a big difference in the way it shot.

IIRC Lucky Gunner covered this in their tests.