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I haven't reloaded for that rifle but have cases from my AR10 .308 that I will reload.  Where are the dents on your cases exactly?  I've notice that the case deflector can sometimes dent a case, but your post seems to indicate a dent caused by the chamber?  Does this POF have feed ramps and the normal feeding profile like most AR's?  Isn't it unusual for a case to be dented during the feeding process in the chamber, barring out-and-out malfunctions?  I don't claim any expertise in this area.  AR's and probably many other semiautos out there can be pretty hard on brass compared to bolt rifles of course.

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Ahhh!...so that's what they were talking about in the recent issue of American Rifleman in their review of the POF P415...I think.  They were talking about the chamber design being more conducive to positive extraction and such...I think.  I don't guess I've ever heard of this type of design before...or maybe didn't really understand what it was.  I've reloaded for years but apparently never had a weapon with this setup.  I gotta ask...is this one of those deals of a solution looking for a problem?  I know lots of AR .308's with proper gas setup and buffer application have no extraction issues at all.  My 2 AR10 .308's have no extraction issues whatsoever with any ammo I've fired through them...and my brass isn't mangled or hacked as a result.  Interesting.  I have a decent amount of respect for POF generally and am kind of surprised that they feel they had to go to this more complicated design to get reliable function.  I have one of their complete lowers from a P415 and love it...no uppers, however.  I found this article, and I guess it's what we're talking about here?...perhaps?

http://www.thefirearmblog.com/blog/2013/04/30/beware-commercial-308-fluted-chambers/

Edit:  I see the POF .308 is a piston rifle.  Is this something more unique to a piston .308 as far as extraction issues go?

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Yes POF made the Gen 4 with four slots or channels of you will in the chamber to help extraction. There some good videos of you google POF Gen 4 made by POF if you want more info. This is not exclusive to the Gen 4 P308 both the Gen 4 P415 also has this design. I'm sure thier full auto P&M versions have them as well. That being said yes many argue that it was "a solution to a problem that didn't exist". I never once had extraction issues with my Gen 3, at least not when I had the gas block in the full open mode. However in the bolt action mode it was pretty hard to extract cases with a standard charging handle. POF does make a modification that allows you to replace the charging handle with what is similar to a bolt (not sure of the terminology but again POF made some pretty descriptive videos on it. For those of you who don't know POF rifles have the ability to change the gas port which constricts gas flow (suppressed) and fully block gas flow (bolt action). Perhaps this is one of the reasons they came up with the new chamber design. But I don't fault them for innovation, maybe the new chamber design works very well in hostile environment conditions or when the chamber is very dirty who knows.

Guess I'll have to solve this riddle on my own