It strengthens it in several ways. And any extra surface area is extra cooling. The more metal “interfacing” with air, the faster it cools.
Sirhr
I'll add some thought to this that I've learned and have seen over the years.
Doing a simple mechanical test a couple of different ways. Using the same contour barrel....... that's important there.
I put both a fluted and unfluted HV contour barrels on a bench center. I put a dial indicator in the middle of the barrel (on the bottom side) and then placed a 20# weight on the top center of the blank. The fluted barrel (going off of memory here) flexed like .020" to .030" more than the unfluted barrel. The fluted barrel had flutes .100" deep.
Taking the barrels and chucking on the breech end in a lathe and did a similar test but hanging a weight off the muzzle. If I recall correctly the fluted barrel flexed less.
Not a great comparison but take a flat piece of sheet metal. Then put ribs in it like a corrugated material. If the ribs run the length wise and you bend it the width wise you can bend/flex it pretty easy but try and bend it the other way and good luck with that.
I agree by adding the flutes it gives the barrel more surface area so more air can get at the steel. This will help it cool faster. Will it help barrel life? I'll say no in the grand scheme of things but it won't hurt ya either.
By fluting the blank you will take weight out. So it will make it lighter.
It's cosmetic. Some like it because of the way it looks.
I would never flute a button rifled or hammer forged barrel. Why? Your dealing with residual stress in the barrel blank and fluting the blank, contouring it etc.... the machining operation will make the barrel steel move around (relieve itself) when this happens the bore will open up/change on you. When this happens you cannot make it go back. Hence forth accuracy will and usually does suffer.
The above isn't a problem with cut rifled barrels but I do feel you can flute the barrel blank too deep. This can also cause harmonic/vibration issues. So as a guide line....
Barrels up to a .750" muzzle diameter we don't go any deeper than .050" on the flutes.
Barrels with a muzzle diameter from .775" to .830" max depth is .075"
Barrels with a muzzle diameter from .850" and larger max depth is .100".
There is also an argument that if one flute is a few thou deeper than an opposing flute that can cause the bore to change when you fire a bullet down it. I get the idea but don't know really how to prove it. I would agree with the theory though.
As far as radial fins are concerned. Is it better than conventional fluting? Beats me. Been around for a long time. The biggest thing I'd be curious about is doing some sort of flexing/measuring set up to see if it flexs more vs a unfluted and fluted barrel. I would gather to say yes it will.
Almost made some replacement DSHK 12.7x108mm barrel blanks but it never happened. Talk about radial cooling fins.....
Later, Frank
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