Fluted vs. Unfluted Cylinders


February 9, 2009, 07:36 PM
I assume the main purpose of a fluted cylinder on a revolver is to reduce weight. Are there any other reasons for a fluted cylinder? Why are some .44 Magnum revolvers fluted while others aren't? For instance, Ruger New Model Blackhawks in .44 Magnum and .45 Colt are fluted, while most of the Super Blackhawks in .44 Magnum aren't. I much prefer the looks of an unfluted cylinder, especially on a single-action revolver, and I can't imagine that it would add that much weight over a fluted one. I can see the reasoning in heavily fluting the cylinder on an airweight J-frame or the new Ruger LCR as those are made to be as light as possible. But in something like a large 6-shot .357 or .44 magnum, how much difference is it going to make? How come my Ruger Single Six Convertible came with a fluted .22LR cylinder and an unfluted .22 WMR cylinder? Just so you can visually tell the difference? Why doesn't Ruger make a stainless, unfluted, 5.5" .45 Colt Blackhawk. I'd buy one in a hurry if they did! My brain is melting, help. Any ideas on the subject?

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Old Fuff
February 9, 2009, 07:52 PM
There are two reasons for flutes:

1. As you suspect, to reduce weight.

2. Cosmetics - in other words, a certain look. ;)

February 9, 2009, 08:11 PM
reason not to:

1) Cheaper

February 9, 2009, 08:14 PM
Why doesn't Ruger make a stainless, unfluted, 5.5" .45 Colt Blackhawk.

Why don't they make a stainless 5.5" .45 Colt Blackhawk at all?

That said, I like this gun:

Note that it has the same grip frame as a Blackhawk, in case you don't like the Dragoon grip on the 7 1/2" and larger Super Blackhawks.

Jim K
February 9, 2009, 08:41 PM
There is another reason for flutes, related to weight reduction, but for a more specific reason. Reducing the mass of a rotating cylinder, especially on the outer edges, reduces the effort required to rotate the cylinder and reduces wear on the mechanisms needed to start rotation (the hand) and stop rotation (the cylinder stop).


February 9, 2009, 08:57 PM
Right on.

Note that the flutes are along the perimeter, where it has the greatest impact on the polar moment of inertia of the rotating cylinder.

February 9, 2009, 09:03 PM
On a totally tangential note, I notice that Freedom Arms has bumped the extra for fluting to 59.00.

Still worth it, IMHO.
Unfluted is OK, just looks the teensiest bit untraditional.

February 9, 2009, 10:16 PM
From what I know, it also stems from the early SA Colts and Smiths. When doing a quick reload, the flutes provide some need traction to turn the cylinder.

February 10, 2009, 02:01 AM
Amongst other things, they "make" or "break" a revolver's style. :D

February 10, 2009, 02:31 AM
I'm a big fan of unfluted cylinders. Sure, they're not traditional. I think that is why they are reserved, sometimes, for special guns, like Freedom Arms, Super Blackhawks -- not just the Blackhawk but the SUPER Blackhawk -- (see?) and others. There are relatively few models available with no flutes, and this lends to their exclusivity. I think, in addition to the other reasons mentioned above, some makers want to give a special distinction to a special revolver.

Jim - Excellent insight; makes perfect sense. I never thought of that.

February 10, 2009, 03:44 AM
My experience:

Unfluted "looks" cool and some buy based on that,

Fluted "works" better and some care about that.

Choose what you want - the manufacturing that cares to make a more functional design, or the "cool" one. I always will go for and pay more for the design that is for function (fluted).

February 10, 2009, 03:56 AM
I actually happen to know the answer to this as I'm a bit of a Ruger addict. :)

The fluted cylinders are traditional for whatever reason. But the nonfluted cylinders of the super blackhawk are part of what makes it a super blackhawk. By design the SBH is made to be heavier to tame the recoil of the 44 mag cartridge. Just like formula one car designers look for places to shave of a few grams here and there, the SBH had the same process done in reverse. A lot of other gun makers have followed suit.

There was an interesting test my father tried back in the day. He had a hard time managing the recoil of his blackhawk .357 mag. He swapped grip frames with a SBH (considerably larger and heavier) and the difference was astounding! He left it like that until he sold it. FYI - these were for the old 3 screw models. I don't think you can swap grip frames on the new models.


February 10, 2009, 09:32 AM
Unfluted is more traditional than fluted. You didn't start seeing fluted cylinders till the 1860's. Today, fluted is more common.

February 10, 2009, 10:56 AM
I admit it, I like the looks of an unfluted cylinder. My 6" 629 and 686 are both unfluted.

February 10, 2009, 11:04 AM
My x25 came with a gimme Clint Smith DVD where he describes using the flutes to index the cylinder for a speedloader or clip.

Though inapplicable to those with loading gates, we can add that to the weight / rotational inertia practical reasons for the things.

Matt Almeda
February 10, 2009, 12:03 PM
I'm not a metallurgist but I'm sure one will come aboard and either agree or disagree.

I believe the reason is that the flutes originally made the cylinder stronger and able to withstand the greater pressures of the smokeless powders. With modern casting and alloys, the flutes were no longer necessary.

Sounds good....but is it true?

February 10, 2009, 06:14 PM
I believe the reason is that the flutes originally made the cylinder stronger and able to withstand the greater pressures of the smokeless powders. With modern casting and alloys, the flutes were no longer necessary.


I'm not a metallurgist


February 10, 2009, 07:04 PM
Flutes are for looks and only for looks. I don't buy the weight argument at all - the amount of weight saved can only be measured in grams, not ounces. Furthermore, Blackhawks with or without the flutes, perform identically. Same with the Freedom Arms.

Weight may have been more of an issue 100+ years ago in relation to less wear on the internal parts, and it only stuck around because that's just what people consider normal on a revolver.

It is neither stronger nor weaker fluted or unfluted - the thinnest part of the cylinder wall always stays the same.

February 10, 2009, 07:08 PM
Flutes provide a blow-out point for overcharged loads.

I just made that up.

Duke of Doubt
February 10, 2009, 07:14 PM
I think unfluted cylinders look like crap, but that's not why flutes are there. It's all about polar moment of inertia, as related above.

No, you don't have to have them. You can have a cylinder with funky little indents and bay windows, if you want. But the flutes are functional, and as a matter of design break up the monolithic cylinder. Sheriff's '62 looks like the cat's meow compared to the Army '60, and I have the Army '60.

February 10, 2009, 07:42 PM
It's all about polar moment of inertia, as related above.

Do you have any idea how miniscule the weight difference really is? Like I said...for OLD revolvers...maybe helpful...but anything modern, no way.

Would anyone happen to have a matching fluted and unfluted cylinder they could weigh?

February 10, 2009, 07:51 PM
All I know for sure is that the unfluted cylinder on my Ruger Bisley Convertible made a great place to put a rollmark. I think it looks better with the unfluted cylinder than with the fluted .45acp cylinder. I can't say I can feel a difference when cocking, firing, or handling the gun though.

February 10, 2009, 08:35 PM
I do have to admit that I'm a lot faster loading full moon clips after watching the Clint Smith blurb on using the flutes. One needn't be looking at the cylinder.

If one were carrying a full moon type defensive revolver for serious social purposes I can see where omitting the flutes could be undesirable.

February 10, 2009, 08:47 PM
Like I said...for OLD revolvers...maybe helpful...but anything modern, no way

An example of a modern revolver would be...?

Didn't fluted cylinders originate with the Colt 'pocket' models? Reduced size revolvers for the style conscious and effete.

Certainly Oscar Wilde would have prefered his....fluted.

February 10, 2009, 09:23 PM
An example of a modern revolver would be...?
Anything labeled "Magnum".

Old Fuff
February 10, 2009, 09:38 PM
Didn't fluted cylinders originate with the Colt 'pocket' models? Reduced size revolvers for the style conscious and effete.

Many of Colt's revolver-style long guns had fluted cylinders, as did early 1860 Army revolvers. They also made a prototype Dragoon "lightweight" with a fluted cylinder.

Fluting resulted in some weight reduction, but the extra milling and polishing operations added to the cost. I suspect that the extra cost of adding flutes whould make unfluted cylinders attractive to today's makers, but buyers now expect the flutes on most revolvers.

February 10, 2009, 10:17 PM
A Ruger is built like a tank. On the other hand, an N frame S&W WILL wear at the hand and rachet faster than a K frame due to the bigger cylinder. So the difference in polar moment due to fluting or the lack of it may be significant in some cases.

February 11, 2009, 08:53 PM
As far as the tradition of flutes goes, I'd define "traditional" not as "first on record," but something more like "a practice started a long time ago, which has been going on continuously since." The dictionary says: "a long-established way of thinking or acting. . ." and "customary or characteristic method or manner . . ." I think fluted cylinders fit both definitions, as they have been the predominant way of finishing cylinders for over a century.

April 2, 2010, 01:37 PM
Matt Alemeda--yes, the flutes increase the strength of the chamber. Don't recall whether I learned this in a Mechanical Engineering or a Metallurgy class, but at the time I believe Ike still shot a decent round of golf.

My metallurgy professor, back in those civilized days, came in to class with an M1 rifle. Stripped it down, we had to decide what metal we would use for each part, how (or whether) we would heat treat it, and how would we make the piece in the first place. That is, forge, cast, stamp, machine from bar, cold draw, &c.

When the piece fires, the chamber is under uniform high gas pressure all the way around. When metal is stressed, it stretches, just like a spring. Removing some metal between chambers makes the expansion (stretch) more uniform, rather than concentrating that strain (stress, if you prefer) on the outside diameter of the cylinder, right over a chamber.

If it were practical to do so, the strongest revolver cylinder would be six smooth tubes, perhaps glued together. Kinda hard to rotate & lock such a device, so fluted cylinders are the best bet.

The earliest fluted cylinders I personally know about were Sam Colt's fluted cylinder 1860 Army. Dunno why he did it. Unfortunately,these cylinders were fluted too far back & burst simply from being too thin at the rear. He replaced these first, mostly burst, cylinders with more fluted cylinders, however the new ones had a tapered chamber so the rear portion near the nipple was thicker.

When any gun fires it is important that the barrel expand as uniformly as possible, to avoid concentrating stresses. Generally speaking, modern firearms are designed to do so.

A cool example of what happens when you restrain uniform expansion is to clamp a modern barrel (without the stock) in a good, strong machinists vice. Load, then pull the trigger. Using a long cord. The barrel cannot expand sideways, because the mass of that large vice restrains it. So all expansion is on the top and the bottom. The barrel will split.

I personally don't personally know if this will always split a centerfire rifle. But in Ancient Times (1940's, 1950's) it was widely known to.

I am not going to argue stress analysis with anyone. If you would like to know more about this, consult a mechanical engineer, preferably one with gray hair.

April 2, 2010, 07:34 PM
There may be something in what JamesKelly states.

Street "wisdom" would have it that the weakest point is the bolt notch, or if it's offset, the center of the outer cylinder wall. How ever, such is not the case. Actual forensic metallurgical analysis shows that catastrophic cylinder failure usually occurs at the web between chambers.

This is the reason for super duper blasto magnums having five holes, thicker webs.

If the bolt notch was the weak point it would be a simple matter to offset the notch as is actually done in several makes of revolver.

Aside from forensic metallurgical analysis showing the failure point to be in the web I've seen the following torture test done on a S&W N frame chambered for 357 Magnum.

Chamber one: The outer side of the chamber was ground flat, level with the bottom of the notch for the entire length.

Chamber two: A slot was cut through the bolt notch for the entire length of the chamber, entirely through the wall.

Both chambers were fired with a standard 357 Magnum load with no failures.

Chamber three: No modification to the camber. How ever, a solid barrel was fitted with no bore what so ever.

Again, fired with no blow outs. (Note, the obstruction was at the barrel breech, not farther down the barrel, allowing the bullet and gas to build up more speed an momentum makes the effects more drastic.)

This is not to say that no cylinder ever failed at the outer wall, but the usual failure is at the web.

Cutting the flute just might allow the outer wall to expand a bit more sideways and relieve stress on the web.

As for the Super Blackhawk, that's so d**n strong the flutes aren't going to matter either way.

Stresses are not always where you think.

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