[NavArch]

I saw a 6.8 FAQ that described three different chamber profiles (SAAMI, SPC II, and DMR) as being the equivalent of comparing the .223 Rem, 5.56 NATO, and Wylde chambers. Does 6.8 SPC ammo come in such different flavors that such a comparison is necessary, or was the FAQ author trying more to describe differences inherent barrel accuracy?

[Hoplophile]

Commercially available 6.8 SPC ammo can be safely fired using any of the 3 chamber profiles you mentioned. Some ammo manufacturers such as Silver State Armory (www.ssarmory.com) sell "tactical loads" that are loaded hotter than original SAAMI specifications. You need an SPC II or DMR chamber to safely use this ammo.

The SPC II and DMR chambers also allow you to load your own ammo hotter than you could with a SAAMI chamber.

[NavArch]

Originally Posted by Hoplophile

The SPC II and DMR chambers also allow you to load your own ammo hotter than you could with a SAAMI chamber.

The write-up I saw implied that the DMR is commonly available only in a custom barrel. What would be the benefit of the DMR over the SPC II?

[ARP]

Originally Posted by NavArch

The write-up I saw implied that the DMR is commonly available only in a custom barrel. What would be the benefit of the DMR over the SPC II?

Accuracy and it has a different cone angle that does not shave copper from the bullet as it enters the chamber, 1 number was transposed on the SPCII reamer drawing and that resulted in a 80 degree corner just in front of the case so as the bullet passes that corner copper can be shaved from the bullet jacket. The small copper shavings get compacted with every case then the heat fuses them together to form a ring at the end of the chamber. It doesn't happen in every rifle but could. The chambers we use are larger to allow reliable feeding when the weapon is dirty and hot but they have a match style throat to align the bullet in the bore better, the chamber is much like the Wylde 5.56 chamber. At the moment we sell CM and SS barrels, we will have some new match grade barrels in a few months and we are not expensive compared to most.

[NavArch]

Thanks for the detailed clarification an the analogy to the Wylde chamber. As an engineer, I can appreciate the differences that small details can create, which is why my 5.56 has a Wylde chamber.