The Myth of Needing a Wider Barrel/Cylinder Gap to Shoot Black Powder

[Driftwood Johnson]

Howdy

From time to time it will be stated on this page, or other pages similar to this, that a wider barrel/cylinder gap than normal is needed when shooting Black Powder to help prevent the cylinder from binding.

I have routinely maintained that this is not true. As evidence I usually state that I regularly shoot Black Powder through a variety of guns, Colts, Rugers, and replica colts, and every single one of them has its original, untouched factory barrel/cylinder gap. They all measure between .005 and .008. I also have moderated this statement by saying that if the gap is really tight, down around .002 or so, it may need to be opened up a bit, but that is the only case when a barrel/cylinder gap needs to be opened up, and even then, .005 - .008 is plenty. The trick, of course, is to use a bullet liberally coated with plenty of Black Powder compatible bullet lube, and the gun should have a good sized cylinder bushing to deflect fouling blasted from the barrel/cylinder gap away from the cylinder pin. Revolvers that are particularly lacking in a good sized bushing are the S&W Top Break reproductions made by Uberti, and the 1858 Remington New Model Army.


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I have always liked the appearance of the Bisley Colt. I'm not talking about Ruger's version of the Bisley, I am talking about the original Colt Bisley. The first Bisley I ever saw was an Uberti replica, and ever since then I have liked the unusual look of the Bisley. I decided that if I ever got the chance, I would love to own one.

Recently I became the proud owner of an original Bisley Colt, made in 1908 and chambered for 44 Special. The barrel and cylinder are not original, the original barrel would have said Bisley Model on it. I am pretty sure this barrel is a 2nd Gen barrel, judging by the way it is marked. The cylinder appears to me to be a 1st Gen cylinder, but I am pretty sure it is not original either since Colt did not chamber the SAA for 44 Special until 1913, and Kuhnhausen says no Bisleys ever left the factory chambered for 44 Special.

None of that really means too much, I was told when I bought the gun that the cylinder and barrel were not original. Nobody was trying to pull the wool over my eyes. I may letter the gun at some point to find out more about it.





But what does all this have to do with tight B/C gaps and Black Powder you ask? Well, it turns out this gun has a very tight Barrel/Cylinder gap. Only around .003. When I bought it, I intended to shoot it in CAS, and of course I intended to shoot it with Black Powder. I already load 44 Russian with Black Powder, and that is what I expected to shoot in the Bisley for CAS.

The first trip to the range was just a shake down cruise with Smokeless 44 Special loads. It performed like a champ, hitting pretty much at point of aim at standard CAS pistol distances.

Next, I took it completely apart, doused all the parts in lacquer thinner to completely remove all oils, then reassembled it, liberally lubing it with Ballistol. This is pretty much my standard procedure for any revolver that I intend to mainly shoot with Black Powder.

My 44 Russian loads have 1.3CC (about 20 grains) of Schuetzen FFg under a 200 grain Mav-Dutchman Big Lube bullet sized to .428 and lubed with SPG. Seating the bullets and crimping them at the crimp groove compresses the powder just a tad under 1/8". I slugged the bore of the revolver, and it came out right at .428. The .428 bullets were also a good fit in the chamber mouths, they just need a little bit of a poke to push them through. My only fear was that with that .003 B/C gap, I might need to open it up a bit.

I grabbed 100 of my BP 44 Russian rounds and headed back to the range. After about 50 rounds the cylinder did start to bind a little bit. Not enough to really be a problem though. By the end of the 100 rounds the gun was complaining a bit, but it was still shooting and cocking the hammer still rotated the cylinder, although it was getting a bit sticky.

I was very happy. Clearly, 100 rounds is much more than I will be putting through it at any CAS match. At any regular six stage match I will probably only be putting 30 rounds through it. Even at an eight stage match, 40 rounds should be no problem, and if it does start to bind a bit, I can always pull the cylinder and wipe it down a bit. Recoil with just 20 grains of FFg is very mild. I may load up some 44 Specials with a little bit more powder in them, or I may just shoot the old girl with those light Russian loads.

[Dick Dastardly]

Howdy Driftwood,

Good report.  Thanks.

Of the Ruger Vaqueros I've had, only three had to be widened at the gap in order to run trouble free with black powder.  Two had the cylinder faces turned and one had the rear end of the barrel shortened.  The .005 to .008 gap seems to be optimum.  I base that on the barrel/cylinder gaps on my ROAs.

One thing I've noticed though is that with lower pressure loads using filler the guns do coke up sooner.  I'm thinkn' your experience with the 44 Russian brass would indicate that a high density load for any given brass tends to burn cleaner.  Also, Schuetzen powder is a cleaner burning powder than some of the others.

Enjoy that fine old gun.  It deserves to be respected and shot by someone that appreciates it.

DD-MDA

[joec]

I had a Uberti Cattleman that would shoot 50 rounds of smokeless or 9 rounds of Pyrodex and hang period. I checked it with a feeler gage and found it had a .0005 gap. Sent it to Uberti and got it back in 5 days with a .006 gap and no more problems. New Cimarron and my old ASM are also both .006 gaps.

[fourfingersofdeath]

I'm normally not all that keen on Bisleys, but that is a fine handgun.

[Dick Dastardly]

FWIW, too much gap can be detrimental to function with black powder also.  The gap needs to be narrow enough that the high pressure flame blows away the fouling in the gap.  I've seen guns that didn't function well with a too wide gap.  Problem is, that problem isn't easily reversible.  So, before you go to taking a mill bastard file to the rear end of your barrel, you better know what you are trying to do.

DD-MDA

[44caliberkid]

Very pretty pistol, DJ.  I love those grips, beautiful.

[Bottom Dealin Mike]

Personally I find Bisleys uncomfortable to shoot, but that is a gorgeous gun.

[Dick Dastardly]

At the Rock River Regulators season opener I did a newbie kind of thing.  I forgot my pistols.  DUH!  Anyway, a fine cowboy (Johnnie Popper) loaned me a brace of 45 Colt Vaquero Bisleys and ammo for same.

I shot a clean match with 'em.  So, even though I'm not quite used to their looks, they do hit where they look.

DD-MDA

[Noz]

I started SASS with a pair of 41 mag Black Hawks. the cylinder gap was in the vicinity of .002-003 on both guns.
When I went to black powder I tried to shoot the Black Hawks for a while and gave up. That was too tight for BP.  I went to Remingtons then settled on the 1860s.

[3Fingers_Murphy]

Hi Driftwood,
Your subject line is confusing because I don't think 5 to 8 is tight. I reread your post and I realized you were just stating the obvious because modern guns are about 3 to 6 from what I have read. Were you responding to someone who was saying you had to have a lot more gap? How much is too wide? I have some Rugers that are hard to cock if I shoot more than a few cylinders of black powder or pyrodex. I can stick a sheet of notebook paper between the barrel and the cylinder so they have to be at least 3. I also have a Navy model that shoots fine and it is really sloppy. I have also seen those cheap guns from Bass Pro Shop that people bring out to the range and have nothing but problems because the gap is too small. I'm not sure it's a myth, my modern Vaqueros get tight but my sloppy old Navy Arms will shoot until I get tired. What was the gap on the old guns in the 1800s?

I have to agree with Bottom Dealing Mike about bisley grips, they don't fit my hand either.I bought a Black Hawk with a Bisley grip and it was fine for slow fire, but I couldn't get a good strong grip on it, my hand was always too low. That gun you show is pretty, mine had the ugliest grips I have ever seen on a Ruger.
Murphy

[44caliberkid]

I think a lot of people's problems with black powder and cylinder binding are from a lack of lube.  The Big Lube bullets cover a multitude of sins.  I've shot the Mav- Dutch in 7 or 8 different pistols, Colt clones, Rugers and an original Smith & Wesson 44.  I've never had a problem with cylinder binding between the cylinder face and the frame.  I have also always lubed over the ball in percussion pistols and never had a problem.  The one time I tried Wonder Wads things were getting tight after 12 shots.   Using lube over the ball I've shot two day matches, 16 - 20 stages, and never did more than wipe off the excess grease.   Lube keeps the powder residue from getting hard, and that's what's binding your cylinder.

[Dick Dastardly]

Howdy Kid,

The new Mav Dutchman molds now have a .015" deep crimp grove.  This was done to keep a usable grove when sized down as far as .427".  The deeper crimp grove came in response to concerns about the grove being too shallow on the original design.  It's the only change.

DD-MDA

[Driftwood Johnson]

3 Fingers Murphy:

I guess I could have been a little bit more plain. I often see it stated that barrel/cylinder gaps need to be opened up to around .012 in order to prevent binding when firing Black Powder through a revolver. That is the 'common wisdom' that I am taking issue with. As I stated, all of my revolvers have their original barrel/cylinder gaps, I have not altered any of them. They all measure between .005 and .008 and I can shoot them all day long without any problems of binding.

I also stated that there are two other requirements to keep the cylinder from binding. One is to use a bullet that carries plenty of Black Powder compatible lube. If one is shooting a revolver with a barrel cylinder gap of .005 - .008, but the bullets do not carry enough soft lube, binding can occur.

And lastly, it is important that there be a raised bushing on the front of the cylinder to deflect powder fouling blasted out of the b/c gap away from the cylinder pin. It is fouling building up on the pin that is more of a culprit in causing binding than fouling building up on the surface of the cylinder.

Here are some examples of cylinders with bushings at the front which direct fouling away from the cylinder pin. Left to right they are cylinders from a Cimarron (Uberti) Cattleman, Ruger Vaquero, and 2nd Generation Colt.






This shows how the bushings prevent binding. The barrel cylinder gap is between the rear of the barrel and the front of the cylinder. The cylinder pin is inside the bushing. It only emerges from the bushing at the very front between the bushing and the frame. When fouling is blasted out of the barrel cylinder gap, it is blasted out pretty much as a disk. The horizontal separation between the b/c gap and the front of the bushing prevents almost all the fouling from reaching the cylinder pin.





Here are cylinders without bushings on the front. They are both for the Remington 1858 New Model Army. The cylinder on the left is a cartridge conversion cylinder made by R&D, the one on the right is the original percussion cylinder.






Here is why the Remingtons bind up quickly when fired with Black Powder. There is nothing preventing fouling blasted out of the gap from being deposited directly onto the cylinder pin. Once fouling is deposited on the pin, it works its way onto the surface of the pin and binds the cylinder.



Schofield reproductions made by Uberti also have problems with BP fouling because the cylinder bushing has been shortened a great deal compared with the bushings on the originals.

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So. My point was, if you use a bullet with plenty of BP compatible lube, AND your revolver has a reasonable bushing on the front of the cylinder, opening up barrel/cylinder gaps beyond about .005 - .008 is unnecessary and may in fact be counter productive. A wider gap may allow more fouling to escape the gap and cause trouble.

The reason I posted in the first place was that I was very happy that my Bisley, with its tiny .003 barrel/cylinder gap, its nice cylinder bushing, and Mav-Dutchman bullets with plenty of SPG lube on them shot better than I was afraid it might. I was afraid that the tight gap might overcome the effects of a lot of BP lube and a good bushing.


P.S. If you don't like the Ruger version of the Bisley grip, you really won't like the grip on my Bisley Colt. The Ruger Bisley grip is not the same as the original Colt Bisley grip. The Colt grip sweeps much farther forward than the Ruger version. Compare the grip shape on my Bisley Colt with the Ruger version.


Ruger Bisley:





Colt Bisley:

[Dick Dastardly]

The Ruger looks like a semi Bisley.  Kind of in between a plow handle and a Colt Bisley.  The Bisley Rugers are what I shot my clean match with.  The grip shape didn't seem to hurt my score, but I'm thinkn' my own Vaqueros with plow handle grips would have done as well, if they'd have been there. . . . .?

DD-MDA

P.S. Blush, shucks, I was shootn' heathen fad smokeyless in them borrowed guns to boot.  I'm on the way to the woodshed.  Feel free to wale away.

[Drayton Calhoun]

I have a fondness for the Bisley myself now, feels odd but shoots great...

[Cuts Crooked]

Schofield reproductions made by Uberti also have problems with BP fouling because the cylinder bushing has been shortened a great deal compared with the bushings on the originals.

Driftwood,

Actually I think that the Uberti Schofields are a problem because the CYLINDER was LENGTHENED, thereby eliminating the bushing. This was done to to make them so that they could be chambered for .45 Colt, which the originals were never made for.
Don't hold me to that, but I seem to recall reading something about this a long time back.

[Driftwood Johnson]

Cuts

You are correct that the cylinders were lengthened over the original cylinders for 45 Colt. I was trying not to get too technical. In fact, the bushing at the front of the Uberti cylinders was not eliminated, it was simply shortened. This photo shows an Uberti cylinder in the front. Notice it has a very short bushing. When Uberti lengthened the cylinder to accommodate the longer 45 Colt round, they did not lengthen the frame a similar amount, but they did not completely eliminate the bushing either. As I said earlier, the shortened bushing does not provide enough horizontal separation from the barrel cylinder gap to effectively deflect fouling away from the cylinder pin.




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By the way, I shot the Bisley in a match today for the first time. Six stages, no binding at all. As a matter of fact, I completely forgot about my concerns until the match was over.

[Cuts Crooked]

Yeah,

I got three  Uberti 75 Remingtons, one a very early production, the other two much later production. The early one has a cylinder that is just a tiny bit shorter, it will chamber 45 Colt rounds, but they best be well within spec, cause the least little bit over and they will stick out the front of the cylinder. However, that particular 75 will run all day every day without any attention. The two new ones will get sticky after three cylinders full.

The difference? The "bushing" on the old one is just that tiny bit longer, putting the "flash disc" a bit further out of line with the end of that "bushing".