The Primary Arms SLx 1-6×24 is a Low Power Variable Optic (LPVO) variable magnification riflescope manufactured by the American company Primary Arms. It has become a benchmark in the entry-level and mid-range segment thanks to its value for money, and is used in a large number of AR-15 sport, civilian and law enforcement rifles around the world.
History and Development of the Primary Arms SLx 1-6x
Primary Arms was founded in 2007 in Houston, Texas, by Marshall Lerner. The company quickly positioned itself as a supplier of affordable optics for U.S. sport and tactical shooters. The SLx (Sport Long Range) range is the brand’s accurate shot-oriented entry-level line, and the 1-6×24 version has been one of Primary Arms’ flagship products since the early 2010s.
The design of the SLx 1-6×24 has evolved through several successive generations, with each generation bringing improvements in optical quality, illumination brightness and ruggedness. Generation III, released in the mid-2010s, introduced Dimitri Mikroulis’ patented Advanced Combined Sighting System (ACSS) reticle system, which combines drop grid, telemetry and wind compensation into one intuitive reticle. The newer Generation IV incorporates ACSS NOVA Fiber Wire technology with Red Dot Bright® illumination comparable to a 1x red dot.
Technical Specifications
| Feature | Specification |
|---|---|
| Officially designated: | Primary Arms SLx 1-6×24 |
| Country of Origin | United States (design) / Asia (manufacturing) |
| Manufacturer | Primary Arms LLC (Houston, Texas) |
| Optical Type | LPVO (Low Power Variable Optic) |
| 1x – 6x | magnification |
| Lens diameter | 24 mm |
| Tube diameter | 30 mm |
| Second Focal Plane (SFP) – FFP option available | |
| ACSS / ACSS NOVA / ACSS Aurora | illuminated reticle |
| 11-level LED illumination, CR2032 battery | |
| Eye Relief | ≈ 4 inches (102 mm) |
| Field of view | 120 ft at 100 yd at 1x – 20 ft at 6x |
| Turret Click | 0.1 mil |
| Overall Length | 10.4 inches (≈ 264 mm) |
| Weight | 17.9 oz (≈,507 g) |
| Housing: | Type II hard-anodized 6063 aluminum |
Operation and Technical Particularities
The SLx 1-6×24 is built on a one-piece tube made of hard-anodizing, hard-anodizing, waterproof and impact-resistant 6063 aluminum. Its main distinguishing feature is the use of the ACSS reticle, a semi-bullet drop combat reticle designed to allow fast aiming at close range and accurate ballistic compensation up to several hundred meters, without the need to manipulate the turrets.
The red LED illumination offers eleven levels of intensity, with enough brightness on the Gen IV versions equipped with NOVA technology to function as a real red dot in direct sunlight. The captured turrets and capped with a 0.1 mil click provide good repeatability, and the SFP (Second Focal Plane) design ensures that the reticle retains its apparent size at all magnifications, simplifying use at 1x. The SLx is generally appreciated for its decent light transmission, generous eye relief of about 4 inches, and mechanical robustness proven by thousands of shooters.
Variants and Versions
The SLx 1-6×24 range is available in several configurations. The SFP Gen IV ACSS NOVA Fiber Wire version is the most advanced version, with red dot illumination. The SFP Gen III version incorporates the classic ACSS reticles in 5.56 / 5.45 / .308. The SFP Gen IV ACSS Aurora version offers a meter crosshair for European users. An FFP version with ACSS Raptor reticle also exists for shooters who want valid graduations at all magnifications. Primary Arms also offers the SLx in 1-8x, 3-9x, 4-14x, 4-16x and 1-10x magnifications on other platforms.
Users and Armed Forces
The SLx 1-6×24 is not a military lens in the strict sense, but it is widely distributed in the United States by sport shooters (3-Gun, IPSC Carbine, NRA High Power), hunters and many rural or small police units looking for a reliable tactical optic at a controlled cost. Several U.S. military reserve units and private shooting schools use it as a training lens. In Europe, it has become one of the most popular LPVOs on civilian AR-15 platforms and dynamic sport rifles.
Civil Possession in Switzerland
In Switzerland, the Primary Arms SLx 1-6×24 is freely available from gunsmiths and optical dealers. As a weapon accessory, its acquisition is not subject to a specific permit, but its use presupposes the legal ownership of the support weapon. For use on AR-15s or other semi-automatic rifles classified as prohibited weapons by the revision of the Federal Weapons Act (Firearms Act) that came into force in 2019, the shooter must have an exceptional cantonal permit within the meaning of Art. 28c LArm, accompanied by proof of regular shooting practice in an affiliated club. On a bolt-action hunting rifle, no specific authorization is required beyond the standard weapons acquisition license.
Conclusion
The Primary Arms SLx 1-6×24 has profoundly democratized access to quality LPVOs over the past decade. Its combination of an innovative ACSS reticle, rugged construction, and an accessible price point has made it one of the most widely used optics in the tactical civil market. It remains an essential reference for anyone wishing to equip an AR-15 without exceeding a reasonable budget, while benefiting from modern features borrowed from high-end military optics.
