For those who want as much power as possible in a very compact package, rifle-caliber pistols are the ideal solution. Growing in popularity, several companies offer them built on either the AK or the AR platform. One potential problem of some AR-pattern pistols is operation. Due to the nature of its operating system, shortening it down to the size of a pistol can introduce functioning problems if not handled correctly. The shorter the barrel, the greater the potential reliability issues. Getting the gas pressure correct is tricky at best. I have found that piston-driven systems seem to have an advantage. In my experience, they just seem to be more reliable in operation when the barrel is shorter than 10 inches.

Primary Weapons Systems (PWS) has been building piston-driven AR rifles for years. In my opinion, the company’s MK107 Diablo was one of the first truly reliable, 7.75-inch-barreled ARs on the market. A hybrid of sorts, its piston-operating system is designed around the venerable AK-47 and stays very close to the original premise. Coupled with the inherent accuracy of the AR platform, the MK107 provides the best of both worlds. None I have tested are as consistently reliable without regard to barrel length as the PWS system.

The new MK107 pistol in .223 Wylde (a hybrid .223 Rem./5.56mm NATO chamber) is the latest iteration of the company’s proven Diablo rifle. Developed as a short-range, CQB powerhouse, it was built with dependable operation in mind.

Read more in the August 2013 Issue of Combat Handguns

For more information, call 208-344-5217 or visit

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