Correct, warmonger, about the drag induced by the rifling ridges.
We are discussing air flow vs. mechanical flow of a bullet. The same theories do not apply.
The ideal air flow passage will be as straight & smooth as possible with no restrictions or protuberances into the air stream. Depending on the designer's intent, of course, the passage could be different than the ideal in regards to surface finish, obstructions, diameter, cross-sectional shape, etc. in order to achieve certain flow parameters.
But generally the rifling idea in regards to air flow is not valid for inducing swirl.
In fact some OEM & aftermarket cylinder heads have combustion chambers designed to induce swirl, but it is induced by the shape of the chamber, not the surface finish.
1999 SVT Contour, #2140 of 2760, Tropic Green - Medium Prairie Tan
Koni Sport struts; TSW Blade wheels; Nakamichi, a/d/s/, Boston Acoustics, Infinity I.C.E.
1989 Saleen Mustang, #89-0408, too many mods to list here
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