Obturation
Member
I like unfluted for a full power revolver but I doubt it adds much besides mass. Mass matters with these things though.
Unfluted means business to me.
Unfluted means business to me.
If you are referring to my 25-7, the SCSW 4th edition calls it a "Glass Bead" finish.What is the finish on that unfluted S&W?
That is the type of cutter used for flutes. It's extremely obvious when they're cut with a ball mill. It's ugly.You could do it with one of these:
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if you had a (manual) horizontal mill. It’s not all that specialized, I didn’t realize it wasn’t an equal radius in both dimensions until I started looking. I’m thinking that since everyone is using CNC, ball-nose end mills might still be more economic. Except that you can CNC a horizontal mill too. Does anyone who can tell the difference have a modern (recently produced) revolver? I don’t.
It would come to play in a single action also if you're trying to shoot fast, especially if your are fanning the hammer or if you're aggressively fast cocking the hammer to shoot fast. Cowboy action shooters see similar wear issues and problems as IDPA/USPSA shooters do in worn pawls and stars, and peened cylinder stops and stop notches.mcb - about that inertia - would that affect single action only revolvers or just doubles when fired "double"? I'm curious as my Single Six is .22LR fluted and .22 Mag unfluted, while my GP-100 (.357) is fluted.![]()
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Wait! Math! Nobody told me there was going to be math. I studied, really I did, but the dog ate my homework.I am always amazed how much attention and conversation flutes or lack there of generates. Being an engineer I wanted to illustrate my earlier point that flutes are a good thing for those of us shooting a lot of fast double action shooting. It's going to get technical, you've been warned!
View attachment 1167932
This above CAD model is based on a S&W N-frame 44 Magnum cylinder. The outside diameter, length, and chambers are correct. Obviously smaller features like the star/extractor, stop notches, etc have been left out for expediency. The unfluted cylinder on the left weighs .212 lb (3.39 oz), and the fluted cylinder on the right weighs .196 lb (3.13 oz) that is only a ~1/4 oz reduction in weight, or 7.6% decrease. Not very much for the amount of machining at first blush, but as far as the pawl and cylinder stop are concerned the torque required to accelerate and decelerate the cylinder between double action shots is proportional to the mass moment of inertia of the cylinder and that has change a fair bit more.
For a linear system the classic equation F = m a (Force = mass times acceleration) holds true. The force is proportional to the mass and acceleration. For a rotational system that same equation looks like T = I alpha (Torque = mass moment of inertia times angular acceleration) Without going into the complexity of mass moment of inertial and how it is calculated, understand that the farther from the axis of rotation a bit of mass is the greater it contributes to the mass moment of inertia. This relationship is by the radius squared so a given bit of mass that is twice as far from the axis of rotation contributes four times at much to the mass moment of inertia of the whole.
So letting the CAD program do all the nasty math, the mass moment of inertia of the unfluted cylinder is .0874 lb-in^2 but the fluted cylinder is .0767 lb-in^2. So the flutes only reduce the mass by ~7.6% but that results in a 12.2% reduction in mass moment of inertia, since all that mass removed was near the outside diameter (as far from the axis of rotation as possible) of the cylinder. So for a given speed of shooting the flutes are reducing the force on the pawl and cylinder stop by 12.2 % If that is fast double action such as in USPSA or IDPA then after several thousands of rounds that difference can be seen in the amount of wear and tear on those parts and the features they interact with.
-rambling
I sort of like that new feature of the updated forum software. Though its going to possibly result in some zombie threads sometimes.If you scroll to the bottom of this thread you can find 5 threads on the similar topic. Way back to 2005!
This is my favorite ramble I’ve read in a long time. Enjoyed the read.-rambling
please what pachmyer grip model # is on that sp101, please.Cutting away metal takes time and tooling, leaving it there costs nothing.
That said, they will put heavy under lugs to add weight and flute the cylinder to remove it…
While machining metal away can lead to stress risers, the people that are saying, that’s not where they fail, are often correct.
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And without flutes, they don’t magically get better.
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please what pachmyer grip model # is on that sp101, please.
Looks a lot like these.
Interesting, never heard of that before. Don't know why a 14 would need one either. Curious to see if they measure it.Curiouser and curiouser
A post on the S&W board shows a LAPD revolver with “beefed up cylinder“. Still fluted, maybe shallower flutes.
LAPD Model 14-1
These pistols are occasionally discussed on this forum and I thought it would be interesting to see one. This one was issued to a friend of mine on Oct 29, 1962. He carried it until he retired in 1982smith-wessonforum.com