Magpul PMAGs designed for the 6.8mm Remington SPC cartridge were developed in partnership with LWRCI. These magazines are larger than the standard GI mags and so far they were only compatible with the LWRCI Six8 series of rifles which receivers were built around these magazines. Apparently, now there is another option on the market – Sulzer Firearms MK1-SPC AR-15 receiver set.

Having the magazine specially made for the cartridge and the weapon build for that magazine/cartridge is always a better solution than trying to fit the cartridge into the magazine and weapon system it was not designed to be used in. That being said, such 6.8 SPC specific receivers and magazines will definitely help to increase the reliability of the build. These magazines and receivers should be a perfect choice not only for the 6.8mm SPC cartridge but for many other cartridges based on it (or rather based on the .30 Remington) which have identical case head and base dimensions. Perhaps the most notable example of such a cartridge is the .224 Valkyrie. These receivers will also be perfect for building a rifle chambered in one of the countless wildcat cartridges based on the 6.8mm SPC case such as the GPC line of wildcat cartridges designed by Mad Dog Weapon Systems.

Below you can find the tech specs of the MK1-SPC receiver set quoted from the Sulzer Firearms website:

LOWER RECEIVER
MODEL: MK1-SPC
MATERIAL: 7075-T6 Aluminum Billet
TYPE: AR-15 6.8 SPC/.224 Valkyrie
FINISH: Cerakote Ceramic Coating (various colors available)

Other Specifications:

• Precision wire EDM cut magazine well with beveled feed lips
• Caliber marking of “Multi” so it can be used with many different caliber uppers
• Take down pin spring and detent hole is threaded for a 4-40 set screw for easy capturing (hardware included)
• Upper tension screw behind grip screw (threaded hole with hardware included) to adjust any play out of vertical fit between upper and lower
• Ambidextrous trigger finger rests with grooves (above and below mag release / mag catch)
• Threaded bolt catch pin (Threaded hole and hardware)
• Integrated large opening “winter” trigger guard
• Uses proprietary magazine catch (included with receivers) for compatibility with Magpul’s 6.8 SPC magazines.
• Manufactured on state of the art CNC equipment for consistent quality parts and exacting tolerances

UPPER RECEIVER
MODEL: MK1-SPC
MATERIAL: 7075-T6 Aluminum Billet
TYPE: AR-15 6.8 SPC/.224 Valkyrie
FINISH: Cerakote Ceramic Coating (various colors available)

Upper receiver may not be compatible with rails that use anti-rotational tabs that slide over the upper receiver without modification to those tabs.

The Sulzer Firearms MK1-SPC receiver set is listed on the company’s website at an MSRP of $349.99. Currently, the set is available at a discounted pre-order price of $309.99.

Images from www.sulzerfirearms.com