By: Friedrich Seiltgen

Copyright © 2022


The first time I saw the company name Quarter Circle 10, I was intrigued.  In 1864, George Washington Saunders was gifted ten head of cattle on his tenth birthday.  Saunders then created the brand Quarter Circle 10 to mark his livestock.  He became a pioneer of the great cattle drives in Texas between 1866 and 1895. He helped organize The Old Time Trail Drivers of Texas in 1915, serving as the group’s president for many years.

George Washington Saunders was the great, great grandfather of Bettina Jary-Mathis, the company founder and owner.  To this day, she continues the long tradition of branding the cattle and horses at the family ranch with Quarter Circle 10.


Well, the 5 comes from the H&K MP-5 magazines it uses, and the YKMF is a line from one of the best Christmas movies ever: Diehard!


Quarter Circle 10 prides itself as being the AR Pistol Caliber Brand: Made for – Not Modified. Every QC10 product is engineered specifically for pistol caliber ammunition, not modified from an existing platform, whish increases functionality, reliability, and overall performance.  All Quarter Circle 10 firearms/parts are made in America.

The YKMF-5 is a 9mm side charging AR pistol.  What sets the YKMF-5 apart is that it’s manufactured with a focus on the MP5 9x19mm magazine.  It features QC10’s adjustable buffer system; it includes high quality parts from trusted partners; and specific attention is paid to detailing the design and aesthetics.  It comes equipped with a 5.5″ QC10 barrel, Bowden Tactical handguard, Dead Air Muzzle Brake, SB Tactical PDW stock, and Phase 5 ambidextrous controls.

While the pistol has the looks of the MP-5, it’s not a roller delayed blowback.  Quarter Circle 10 uses their own adjustable buffer system that lets the shooter add or remove weight from the buffer, depending on the type of ammunition used.


Type: Direct Blowback

Caliber: 9x19mm

Magazine capacity: 30

Sights: Full length picatinny top rail to mount your choice of Optics.

Barrel Length: 5.5 Inches

Overall Length: 21 3/8 – 23 7/8 Inches

Weight: 5.14 Pounds

MSRP: $1,775



I’d say the YKMF – 5 is a buy!  Quarter Circle 10 is known for its quality firearms.  They build their guns specifically for each caliber.  I don’t want to give out my hard-earned cash on gun parts thrown together with sub-standard junk.  An added bonus is that Quarter Circle 10 is a staunch supporter of the 2nd amendment that puts their money where it counts, supporting various Second Amendment Non-Profits.

That’s all for now folks!   Please keep sending in your questions, tips, and article Ideas.  And as always – “Let’s Be Careful Out There”

Friedrich Seiltgen is a retired Master Police Officer with 20 years of service with the Orlando Police Department.   He conducts training in Lone Wolf Terrorism, Firearms, and Active Shooter Response.  His writing has appeared in RECOIL, The Counter Terrorist Magazine, American Thinker, Homeland Security Today, and The Journal of Counterterrorism & Homeland Security International.  Contact him at