Boise, Idaho-based firearms manufacturer Primary Weapons Systems (PWS) is releasing a new briefcase designed for SBRs. The interior of the case contains four cutouts which fit the MK107 upper, two Magpul Pmags and a PWS MK1 Pistol Lower fitted with the SB15 Pistol Stabilizing Brace by Sig Sauer. The leather briefcase itself was designed by Kenneth Cole and customized by Bauer Cases. As PWS’ official website states, this fitted, lined briefcase is being sold with an MK107 upper receiver at the same cost of a stand-alone MK107 upper. The Firearm Blog lists the MSRP of the case and MK107 upper at $1,449.95. Essentially, if you buy the MK107 upper, you’re getting the case for free.

Chambered in .223 Wylde, the PWS MK107 boasts a 7.75″ barrel and an overall length of 23.75″. “The short, compact design retains lethal capability out to 200 meters and has been proven highly effective with very little sacrifice over a standard rifle,” the PWS product listing reads. It has a muzzle velocity of 2368 ft/sec and a muzzle energy of 772 ft-lbs. The upper comes with a Triad 556 flash hider, which reduces muzzle rise by redirecting the gases which are exiting the muzzle. MSRP is $1,949.95.

Specifications: PWS MK107

* Caliber: .223 Wylde
* Weight: 5 lbs, 4 oz
* Overall Length: 23.75”
* Barrel Length: 7.75”
* Muzzle Velocity: 2368 ft/sec
* Muzzle Energy: 772 ft-lbs
* Muzzle Device: Triad 556
* MSRP: $1,949.95

For more information about the new briefcase for MK107 uppers, and the full range of products currently offered by Primary Weapons Systems, please visit

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