I've been researching rifling and am really intrigued by the polygonal (and hybrid) rifling claims of better accuracy and less bullet deformation. I know REVolution Arms does this, as does MicroMOA Any others? Does it -the accuracy- really get better? If so, are there other manufacturers engaged in doing this? I'm thinking of doing another build of a military competition match rifle (A2) and using one of these barrels.

Noveske does.

I know polygonal rifling is supposed to make a better seal around the projectile/ use gasses more efficiently/ improve muzzle velocity. Glock HK and a few other companies use it. Never knew that processed migrated to rifle barrels.

Thanks for the Neveske tip (expensive compared to others it seems). So that makes three so far : Noveske, REVolution Arms and MicroMOA (are their barrels their own?)

Noveske is worth it. Check out Molon's review of an 18" Noveske. Some say they are spotty as far as quality goes since John passed. The 16" I have shoots bulk PMC pretty dang good. Honestly Larue has their barrels on sale right now and I would just jump on that if your thinking about buying a barrel. Doesn't have the polygonal rifling but they are very good barrels. Look at the MOA challenge and it speaks for itself.

Frank Green of Bartlien barrels has done extensive testing over a large number of barrels and states there is no perceivable difference. The only reason they bother making them is because customers keep asking for them. I would take his experience of pretty much any in the industry. Krieger' website list the same "benefits" for 5R rifling (not quite polygonal, but same idea) as Bartlien's, but if you actually talk to one of their techs, they say there are no measurable differences. When the top barrel makers that are actually selling them tell you it's just marketing, that means something.

But if you really want one, go ahead and try it. I haven't heard any downsides to them. Just don't turn down a known good barrel because it doesn't have it.

ETA: The top 9 ARs in the MOA challenge thread use standard groove barrels. Not sure what the DD barrel at 10 uses.

5R rifling isn't really that much different than Enfield rifling




Black Hole Weaponry uses 3-lobe Caudle rifling.  They make barrels for Black Rain as well.
In my experience they can be just as accurate and will squeeze a few more FPS from similar short barrels.

Not sure about accuracy or velocity, but polygonal rifling is easier to clean (fewer nooks and crannies, per se)

The lack of corners probably gives the tooling a bit longer life and would definitely decrease the tooling stress in hammer forge type operations.