Seekins Precision SP223 Gen 2 6mm ARC Semi-Auto Rifle – 22" Stainless Heavy Barrel, Custom Billet Build
This custom-configured Seekins Precision SP223 Gen 2 pairs a 22-inch stainless heavy barrel with the flat-shooting 6mm ARC cartridge for long-range precision from a familiar AR-15 platform. Built on matched billet receivers, it features ambidextrous controls, a free-float M-LOK handguard, and premium Magpul furniture, offering a well-thought-out package for serious shooters who want excellent accuracy and modern ergonomics.
Condition
Overall Condition: Excellent condition, showing only faint signs of any prior use or handling.
Bore Condition: Excellent – clean, mirror finish, no signs of wear.
Bore Rifling: Excellent – sharp lands and grooves.
Specific Condition Notes: The rifle displays mild evidence of use but has clearly been very well cared for.
What’s Included
- Seekins Precision SP223 Gen 2 6mm ARC rifle
- Magpul PMAG Gen M2 MOE 30-round magazine
- Magpul PRS Lite adjustable stock (installed)
- Magpul MOE+ rubber-overmolded pistol grip (installed)
- Magpul M-LOK Angled Fore Grip (installed)
The heart of this build is Seekins Precision’s SP223 billet receiver set, machined from 7075-T6 aluminum and finished with a durable black anodize. Ambidextrous bolt catch/release and safety levers streamline operation for either hand, while screw-in dowel pins replace traditional roll pins for easier maintenance.
Chambered in 6mm ARC, the 22-inch stainless heavy barrel maximizes velocity and stability for long-range work. A 5/8-24 threaded muzzle invites the addition of a suppressor or brake to further tune recoil and report.
The rifle’s extended free-float handguard keeps the barrel completely isolated from external contact. Spiral lightening vents, M-LOK slots along the sides and bottom, integral QD cups, and a full-length Picatinny top rail give shooters abundant mounting options without excess weight.
Ergonomics come from Magpul’s PRS Lite stock, adjustable for length of pull to 15 inches, and the MOE+ pistol grip with rubber over-molding for a firm grasp. Together with the angled fore grip, these components promote a balanced, controllable feel whether shooting prone, benched, or from improvised positions.
With its precision-oriented barrel, billet construction, and thoughtful control layout, this SP223 Gen 2 is ready to stretch the legs of the 6mm ARC round while maintaining the familiar handling of an AR-15.