Please be aware that all orders are currently on backorder delay until March 2021. Contact Info@quartercircle10.com with any questions.
Quarter Circle 10, THE AR Pistol Caliber BRAND. Leader in top of the line, dedicated AR15 Pistol Caliber parts. 9MM Universal Bolt Assembly
Shipping: All orders are shipped within 72 hours Monday - Friday 8am - 5pm PST
Any order containing a lower receiver will not be shipped until we receive a copy of your FFL. Once received regular shipping policies apply. Submit your FFL Here.
Returns: Quarter Circle 10 offers a 30 day return, refund and exchange policy. See Details.
Advanced blowback design
Manufactured to function reliably with any QC10 9mm platform. Glock, Sig226, MP5, and CLT9MM magazines supported.
Drop-in Installation
8620 Steel Bolt
QPQ Nitride treated for maximum durability and wear resistance.
Heavy Duty Extractor
Removable mass