Primary Arms SLx 1-6x24 SFP Gen IV ACSS Nova vs Primary Arms SLx 4.5-27x56 FFP
Primary Arms SLx 1-6x24 SFP Gen IV ACSS Nova is a 1-6×24 SFP on a 30 mm tube with MRAD turrets; Primary Arms SLx 4.5-27x56 FFP is a 4.5-27×56 FFP on a 34 mm tube with MRAD turrets. The Primary Arms SLx 1-6x24 SFP Gen IV ACSS Nova is lighter by 15.3 oz. The Primary Arms SLx 1-6x24 SFP Gen IV ACSS Nova has more elevation travel, 120 MOA to 110 MOA in the same unit. At its top magnification the Primary Arms SLx 1-6x24 SFP Gen IV ACSS Nova keeps a 4 mm exit pupil against 2.1 mm for the Primary Arms SLx 4.5-27x56 FFP — estimated from the layout, not measured. On our last catalog check the Primary Arms SLx 1-6x24 SFP Gen IV ACSS Nova listed for about $150 less.
| Spec | Primary ArmsPrimary Arms SLx 1-6x24 SFP Gen IV ACSS Nova | Primary ArmsPrimary Arms SLx 4.5-27x56 FFP |
|---|---|---|
| Approx. price | ~$350 | ~$500 |
| Magnification | 1-6× | 4.5-27× |
| Objective lens | 24 mm | 56 mm |
| Focal plane | SFP | FFP |
| Reticle | ACSS Nova Fiber Wire | ACSS Athena BPR MIL |
| Illuminated | Yes | Yes |
| Turret unit | MRAD | MRAD |
| Per click | 0.1 MRAD (0.36″ at 100 yd) | 0.1 MRAD (0.36″ at 100 yd) |
| Elevation travel | 34.9 MRAD (≈120 MOA) | 32 MRAD (≈110 MOA) |
| Windage travel | 34.9 MRAD | — |
| Zero stop | No | Yes |
| Turrets | Capped | Exposed |
| Parallax | — | Side focus |
| Eye relief | 4″ | 3.5″ |
| Field of view | 120–20 ft at 100 yd | 23.4–4.1 ft at 100 yd |
| Tube | 30 mm | 34 mm |
| Length | 10.4″ | 14.4″ |
| Weight | 17.9 oz | 33.2 oz |
| Warranty | Lifetime | Lifetime |
| Exit pupilest. | 24–4 mm (1×–6×) | 12.4–2.1 mm (4.5×–27×) |
| Twilight factorest. | 12 at 6× | 38.9 at 27× |
| Zoom ratioest. | 6× | 6× |
| Where to buy | Primary Arms → | Primary Arms → |
Tinted rows are where these two differ. Rows marked est. are computed, not published.
Exit pupil and twilight factor are computed from the published magnification and objective diameter, not measured. Real exit pupil is also capped by the erector at low magnification, and coatings and glass quality move low-light performance in ways the formula cannot see — read these as comparisons between layouts, not verdicts on scopes.