I'm putting together a .308 AR and I was wondering if anybody has any experience with the ones from Rainier and if they are cold hammer forged as opposed to button rifled [IIRC Polygonal rifling is usually on cold hammer forged barrels]
Anybody?

If they're the poly rifling they're made by Black Hole Weaponry. I only use those barrels and they're damn fantastic, and very easy to clean. For my personal guns I don't use anything else.

Good people and products at BHW...Even if you have a problem with their barrel they will do the customer right and replace it....

I use them exclusively for all my AR barrel needs...their prices are also reasonable as is the turnaround time...

Good Luck.

Polygonal rifling is done the same way button rifling is done with just a different insert (according to Lothar Walther)

So far I like my BHW barrel...

Is this according to Rainier Arms?  I read that Rainier Arms uses PacNor barrels for match grade.

BHW poly rifling and Rainier poly rifling are two completely different types of rifling.

My 6.8 Ultra Match is a Shilling.

Shilen

Ah, so polygonal rifling can be either button rifled OR CHF.  Thanks for the clarification.  CMMG is advertising CHF polygonal rifled barrels BTW.  Price is a little steep for something with no reviews yet, and I know Rainier has gotten some pretty good reviews.  Anyway, Still, the poly rifling sounds about my "speed" if you'll pardon the pun.  ;)
And I can get the 20" from Rainier already.
The BHW and Rainier's certainly sound similar as they both use three groove poly rifling.

Cool,

Hammer forging is the cheapest way to make a barrel.  A rifled mandrel is inserted is a steel tube and then the tube is hammered around its ircumference  in a press.  This method causes a lot of stress in the metal.  As the barrel heats, the stress causes the barrel to flex in an unpredictable way.

Best stick with button or cut barrels that are stress relieved and hand lapped.

PCM

Rainer's are Shilens hence the term "ratchet rifling".

True polygonal rifling is shaping the internal surface of the barrel into a polygonal shape, and rotating that shape to form a twist. Think Glock barrel. There are no lans or grooves.
BS marketing polygonal rifling is altering the edges of the lans and grooves in conventional rifling to create a lan crossection of a shape other than a square or rectangle. Its not really polygonal rifling, and it doesn't buy you a damn thing. Don't pay extra for it.
Conventional rifling (L) Polygonal rifling (R)

See, I've heard the opposite about CHF in that it makes the steel denser, and you don't get tool marks down the barrel that have to be lapped off to smooth it out.  Where did you get your information that it makes the barrel "warp" in  odd ways?
I haven't seen the CMMG rifling pattern yet, however the Rainier and BHW barrels are both advertized as "three groove" polygonal, and only the BHW is actually shown.  Where do you get the information that the Rainier is completely different and how is it different?  I'm hearing a lot of hear say here.  Anybody can claim to be an expert on the interwebs, which is why I ask for references to back up claims.  Remeber, theres mucho crap out there on how horrible the AR platform is, yet here we all are, knowing different from doing research and reviewing the actual information rather than some "expert's" opinion that "Them M16s and AR15s are all crap".

I own a Glock, I've also owned other weapons with polygonal rifling.  I know the difference betwen polygonal, sinusoidal [sp], and traditional rifling, however, thanks for making sure the info was posted for those who don't know the difference.

Copied from the description of the barrel I am interested in over at Rainier:

So where did you get the information that they are using Shilen ratchet rifled barrels [which as far as I can tell only come in 4 and 6 groove, not 3 groove]?

It creates a lot  of stress on the barrel.  See this article from Lilja's website:  http://www.riflebarrels.com/articles/barrel_making/details_of_accuracy.htm.  It says that:

There is a reason you never, ever see a benchrest hammer forged barrel.  The most accurate barrels are button or cut rifled.

I'm going to have to do more research because there are varying views on this, as evidenced by the attached link

https://technology.calumet.purdue.edu/met/higley/Precision%20Shooting%20Magazine%20-%20November-%202005%20(Vol_%2053%20-%20No_%207).htm

The only reason I sometimes question evaluations of "this process is better" or "that process is better" is that generally, if its a manufacturer telling me his barrels are better, I tend to be suspicious as hes trying to sell me his barrels in the first place.
I'm not saying that the claims that button rifling is better are wrong, I am saying I would like to get confirmation on that from an independent/non-biassed source

Some of Rainier's are polygonal, some are Ratchet, some do not say, at least in their 5.56/Wylde barrels.  I have not looked at others. They are not the same thing.  Shilen use ratchet rifling, not polygonal, so it seems Rainier uses Shilen barrels (which they state outright) for their Ultra Match, but not their select.

Hopefully one of the techies can clear it up but 3 groove poly rifling is not the same as a true poly bore like HK and Glock use. My understanding is it is more of just a rounded rifling like the 5R type stuff.

5R type stuff?
I'm looking for a good, long wearing, decently accurate barrel.  This is not for a bench rest rifle, its a working rifle
BTW, HK, Steyr, Sako, and many other manufacturers seem to use CHF barrels for MANY of their "sniper/counter sniper" type precision marksman rifles.  If it was so bad for the accuracy of the barrel, then why do they still use it?
In all honesty, unless you are trying to wring every last thousandth of an inch of accuracy out of a rifle, with no interest in longevity, then yes, CHF seems to not be the way to go, how ever, I am not a bench rest shooter.  I am a practical rifleman.  If I can keep all the shots in a 10 circle at 500, I will be more than happy.  If my barrel will hold up for the long term, I'll be even happier.

Thanks for the input, guys.

Any of the name brand barrels will do what you need. Rainier makes good stuff so if you like it buy one and start sending rounds downrange.