Fluted vs. Unfluted Cylinders.

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dayman

New member
First, let me start by saying that I prefer the look of an unfluted cylinder.

But I have a question.
I know that milling flutes into the cylinder - at least in theory - should make the chambers stronger. I might be remembering my Strengths of Materials classes all wrong, but having a more consistent wall thickness should make the chamber less prone to rupturing.

So, why - at least with Ruger - are all the lighter calibers fluted, and the biggest calibers unfluted? - .454, .480 SRH, and a few of the .44 SBH models.
Is it entirely a looks thing?
Is the strength gain from fluting a cylinder so low that it doesn't really matter?
Is the strength gain one of those things that works out in a "every piece of steel is 100% perfect" physics equation, but doesn't work in practice?
Or, does the fact that flutes (as commonly made) add some corners to the chamber wall actually make them weaker.
Or is it something else entirely - is having a heavier cylinder somehow a good thing in a gun with that much recoil?


It's been too long since I took the right kind of physics to figure that out myself, and asking seems easier that digging through the attic for my old text books.
 
I know that milling flutes into the cylinder - at least in theory - should make the chambers stronger
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Hmmm...

I thought it was exactly the other way around, and that the fluting was to save weight...
 
As an addendum, it is my understanding that fluted barrels on rifles tend to be stiffer, but the flutes lend nothing to the burst strength...
 
Flutes on a rifle barrel will reduce weight, but leave the barrel "ALMOST" as stiff as if left unfluted. It is a decent compromise on weight reduction while still maintining accuracy. You will lose some stiffness with a fluted barrel, but it will still be better than a non-fluted barrel of the same weight. Not quite as good as a non-fluted barrel of the same diameter.

On a revolver cylinder it is also for weight reduction as well.
 
I know that milling flutes into the cylinder - at least in theory - should make the chambers stronger. I might be remembering my Strengths of Materials classes all wrong, but having a more consistent wall thickness should make the chamber less prone to rupturing.
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You're going to have to explain how adding metal makes the cylinder weaker.

Most revolvers use fluted cylinders to reduce both overall weight and especially rotating weight, which has an effect on double action trigger pull. The weight of the loaded cylinder has to be started and stopped on every DA shot and the less of it there is, the easier the task.

Really powerful revolvers need the extra weight to deal with the recoil and DA pull is not such an important characteristic with them.
 
Fluting a rifle barrel also helps with cooling.

Fluting a revolver cylinder, however, does NOT make it stronger.

As others have noted, it's done primarily for weight and aesthetics. In the early days of cartridge revolvers like the Single Action Army, it gave the shooter extra purchase on the cylinder, thus making it easier to turn it while reloading.
 
Flutes on a rifle barrel will reduce weight, but leave the barrel "ALMOST" as stiff as if left unfluted. It is a decent compromise on weight reduction while still maintining accuracy. You will lose some stiffness with a fluted barrel, but it will still be better than a non-fluted barrel of the same weight. Not quite as good as a non-fluted barrel of the same diameter.
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Thank you for the clarification...
 
I would agree with Mike..
The flutes would make reloading only take half a day since you can grab ahold of the cylinder and turn her easier...

Funny how early BP are all (mostly?) non fluted...nothing short of a spare preloaded cylinder would speed up THAT process...lol
 
Jeff Cooper once wrote that in the one destructive test he had seen, an unfluted Ruger SBH cylinder burst before the fluted S&W M29 but he considered it academic since pressures were approaching triple normal at the time.

For extreme rapid fire, the flutes reduce cylinder weight. This reduces the effort on SA hammer or DA trigger to start rotation and reduce the impact on the cylinder stop/bolt. Some fast draw guns have very deep flutes and thin chamber walls since they will only be shooting blanks or wax. Some of the action shooters go so far as to get titanium cylinders made for fast DA.
 
Wouldn't fluted revolver cylinders distribute the pressure slightly more evenly, making it stronger? On an unfluted cylinder it seems it would put more pressure on the metal between chambers.
 
The weakest point in the revolver's cylinder will remain the same fluted or not. The escaping pressure (in the case of a rupture) will only know where the weak part is. You could change the dynamics of the rupture by changing the weak area, but not by strengthening a strong area and leaving the rest alone.
 
As far as I know the lack of flutes don't really add that much useful strength to the cylinder at all. A bit perhaps but nothing useful.

The area of the cylinder that will blow is the area where the wall is the thinnest. That area is the same on fluted and unfluted cylinders.

As others have mentioned the unfluted cylinder does add weight and it may look good but if a cylinder is to blow they will both blow at the same place and point.

As far as heat dissipation being a factor, that is not so likely.

tipoc
 
Wouldn't fluted revolver cylinders distribute the pressure slightly more evenly, making it stronger? On an unfluted cylinder it seems it would put more pressure on the metal between chambers.
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That's what was thinking. It apparantly doesn't really apply to revolver cylinders, but a thin pipe will hold up to pressure much better than a thick pipe with a thin spot.
Removing the right material can definitely make things stronger. Grinding down ridges for example.
It has to do with the way force is distributed through the metal. A thin spot winds up collecting a lot more force. To hugely oversimplify it (for my own benefit as much as any one else's), if everything can flex a little it holds up better than if only one patch can flex - the transition between flexing parts and static parts becomes a weak spot (we're talking, like nanometers of flex - nothing visible).
But, I also remember the effect is mitigated by smoothing out the transition between thicknesses - which definitely happens in a revolver cylinder since everything is round.
Obviously I'm not sure, and I'm probably wrong, but it seems like the thin wall between the chamber and the outside of the cylinder could wind up being a weak spot.
Or, apparently not.
.... again, it's been 5-6 years since I was in college, and I've done very little with Strength of Materials since.
Clearly it's a non issue. I was just curious if anyone knew.
It seems like added weight is the reasoning behind leaving them unfluted, which makes sense.
 
Consider that if a round is going to blow, an overloaded reload let's say, and it is strong enough to destroy a fluted cylinder it will also be strong enough to destroy or damage a non fluted cylinder. In the case of the non fluted cylinder there may be less shrapnel to fly about but both will be destroyed.

Keep in mind that a cylinder can also be destroyed without blowing to pieces-the walls of the chamber, for example, can be bulged to the point that the gun is unsafe or inoperable.

In the pics below of a S&W M29-2 note how thin the walls of the cylinder are in both the areas of the notch for the cylinder stop and in the wall thickness on the edge of the cylinder. Note that the cylinder did not blow in the area of the flutes.







So while a non fluted cylinder may have a small amount of strength over a fluted one it is not any that makes a difference other than maybe less shrapnel in the case of a catastrophic blow up. If something will destroy a S&W cylinder it will also destroy or damage a Ruger cylinder.

tipoc
 
Very nice graphics, tipoc. I think there is no question that esthetics are a big part of the reason for unfluted vs fluted cylinders. Each style has its fans.

To address the issue of Strength of Materials raised by the OP, consider that Ruger is designing the .480 revolver to withstand a certain amount of pressure along with a safety factor. It could be that both cylinder designs use the appropriate alloys and material design to withstand the pressure of .480 Ruger and .454 Casull but possibly there is greater margin with the unfluted cylinders. I don't know Ruger's thinking but it makes engineering sense that Ruger would want the cylinder to be not only strong enough but as strong as possible for its most powerful calibers.

Recall that the SRH .480 revolvers were 5 shot before they were initially introduced about 10 years ago. Now the new versions are six shot. There were some issues with the earlier version of the .480 revolver and these issues were well covered in older threads on this and other forums. Probably, Ruger made some engineering changes going to the new version but I am unable to find any detailed information on the specifics.
 
Can't say if its true....

But I remember hearing somewhere that the fluting of revolver cylinders started as an attempt to fix a cracking issue with some cylinders. And it was carried on as "tradition", because it was what the buyer had come to expect.

Fluting does save some weight, and gives black powder fouling someplace to go. in an SA gun (particularly the early cartridge conversions) it also gives the shooter a means of indexing the cylinder in the dark (by feel).

It might not have been marketed as such, but it would make reloading in the dark (with cartridges) easier.

NON fluted cylinders are an easy way to add (or keep) weight in the gun, which helps reduce felt recoil. Other than that, its just appearances. Any difference in ultimate strength are immaterial, as it occurs at the blow up point, NOT the shooting point.
 
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