Arken EP5 5-25x56 FFP vs Primary Arms SLx 4.5-27x56 FFP
Arken EP5 5-25x56 FFP is a 5-25×56 FFP on a 34 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 4.5-27x56 FFP is lighter by 6.0 oz. At its top magnification the Arken EP5 5-25x56 FFP keeps a 2.2 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 4.5-27x56 FFP listed for about $100 less.
| Spec | ArkenArken EP5 5-25x56 FFP | Primary ArmsPrimary Arms SLx 4.5-27x56 FFP |
|---|---|---|
| Approx. price | ~$600 | ~$500 |
| Magnification | 5-25× | 4.5-27× |
| Objective lens | 56 mm | 56 mm |
| Focal plane | FFP | FFP |
| Reticle | VPR MIL | 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 | 32 MRAD (≈110 MOA) | 32 MRAD (≈110 MOA) |
| Windage travel | 16 MRAD | — |
| Zero stop | Yes | Yes |
| Turrets | Exposed | Exposed |
| Parallax | Side focus from 25 yd | Side focus |
| Eye relief | 3.4″ | 3.5″ |
| Field of view | 25.3–4.9 ft at 100 yd | 23.4–4.1 ft at 100 yd |
| Tube | 34 mm | 34 mm |
| Length | 14″ | 14.4″ |
| Weight | 39.2 oz | 33.2 oz |
| Warranty | Lifetime Warranty (manufacturing defects, original purchaser) | Lifetime |
| Exit pupilest. | 11.2–2.2 mm (5×–25×) | 12.4–2.1 mm (4.5×–27×) |
| Twilight factorest. | 37.4 at 25× | 38.9 at 27× |
| Zoom ratioest. | 5× | 6× |
| Where to buy | Arken → | 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.