What would you like to know about a 6.5mm PPC AR15.  I started the project in 1998 and have been shooting it for almost 3 years.  I can actually say, I have the first given that the chamber reamers and reloading dies were custom created for my project by JGS Tool and Redding.  

In brief, I shoot 128 grain Cauteruccio bullets at 2750 fps from the magazine.  BC on these bullets is .560.  Accuracy wise, .5 MOA groups at 300 yards and popping tennis balls at 500 yards are easy.

As far as reliability, the only issue is that magazines need to be tuned to work with the PPC or even the 7.62x39.  Not a big deal,,just a bit of massaging with a pair of needlenose pliers.  Once done, they work well.

Feel free to email

Finding the right gunsmith to do a PPC is critical.  Many can do a .223 Remington, but alot depends on what reamer they are using.  The other issue on alternate calibers like 6mm and 6.5mm, is the gas port size and location.

Scott Medesha or Derrick Martin are best suited to do a PPC as a custom so you dont end up with a lemon. One big positive is they are friends and share knowledge.  Beyond that, they have made various versions of the PPC in an AR.   Scott did my 6.5 PPC in 1999.

As a comparison of .22, 6mm and 6.5 bullets in an AR

.224 - 80 grain (BC=.500)
.223 Rem at 2.450"+ to achieve 2750 fps - will not fit in a magazine.  
22 PPC at 2.255" OAL = magazine length.

6mm - 107 grain (BC = .540) will be at 2.350" OAL in a 6PPC - will not fit in magazine.  
In a 6mmx47,,the 105-107 grain bullets would make the OAL even longer.

6.5mm - 128 grain (BC = .560) will be at 2.255" OAL in a 6.5 PPC = magazine length

If you are building a serious rifle, the whole point of using an AR15 is to have a semi-auto with magazine fed rounds.  While an 80 grain will work in a 22 PPC magazine length,  in the 6.5 PPC, you have magazine length and better ballistics

For those that are interested, the 6.5 PPC will no longer be a wildcat and will become a production offering in the AR15.

Alexander Arms (maker of the .50 Beowulf) will be offering this round under the name of .26 Grendel.  They will have flat top carbine and rifle uppers, factory brass made by Lapua, loaded ammo, reloading dies and 10 round magazines that are manufactured specifically for the PPC.  For law enforcement and the military, there will be a 25 round magazine.

Currently, the only mention on the Alexander Arms website (http://www.alexanderarms.com) is under the military section.  It lists the .26 Grendel under development.