US Optics FDN 10x42 FFP

• Fixed 10x configuration: A single 10x magnification keeps the sight picture consistent, which helps with repeatable holds, faster target confirmation, and a simpler shooting workflow at distance.
• First focal plane illuminated reticle: The FFP reticle stays proportional through the optical system, so subtensions remain useful for ranging and holdovers, while daytime-visible red illumination improves reticle visibility against dark targets.
• ER3K zero-stop elevation system: The tactical elevation turret combines 48.00 mrad of travel with a Zero Stop, making large corrections practical while allowing a fast, confident return to zero.
• Side focus with integrated illumination control: Parallax adjustment from 30 yds to infinity helps sharpen the image and reduce aiming error across changing distances, while the integrated control layout keeps operation compact and efficient.
• 34 mm aluminum tube construction: The 34 mm tube, nitrogen filling, and waterproof, fogproof, shockproof build support dependable use in hard field conditions where weather and recoil can quickly expose weaker optics.

About the US Optics B Series

The US Optics B Series was built around magnification ranges favored by professional shooters, giving the line a clear role as a practical tactical riflescope family rather than a general-purpose hunting optic. The series includes the B-10, B-17, and B-25, covering compact mid-range use through more dedicated long-range work. Across the range, U.S. Optics emphasized a control layout meant for field handling: locking elevation and windage knobs, the EK2 stop, a revolution counter, and tool-free elevation zeroing.

A defining characteristic of the series is its integrated approach to controls. Reticle illumination is built into the parallax knob and operated by a single button, which keeps the scope body streamlined and reduces unnecessary external clutter. B-Series models were also offered with either 1/10 mil or 1/4 IPHY adjustments, allowing shooters to choose a system that matches their preferred reticle and correction method. In late 2019, U.S. Optics announced that the Foundation Series would replace the B-Series, but the B-Series remains important as a bridge between the company’s earlier custom-oriented designs and its more standardized modern tactical optics.

About the US Optics FDN 10x42 FFP

The US Optics FDN 10x42 FFP is a fixed-power tactical riflescope built for shooters who want the consistency of a dedicated 10x optic rather than the added complexity of a variable system. That fixed magnification is well suited to disciplined prone shooting, practical field use, and rifles set up around known-distance work, because the image scale and reticle appearance remain constant from shot to shot. Paired with a 42.00 mm objective lens and a 4.20 mm exit pupil, it balances usable brightness with a compact overall form.

The reticle sits in the first focal plane, which is especially useful on a precision-oriented scope because hold values remain true in relation to the target image. Combined with red illumination that is stated to be daytime-usable, the reticle stays easier to pick up against dark backgrounds, shaded targets, or cluttered terrain. The side-focus system adjusts from 30 yds to infinity, helping maintain a sharper image and reducing parallax error as target distance changes.

Mechanically, this model is configured for practical dialing. The tactical turret system provides 48.00 mrad of elevation and 28.00 mrad of windage adjustment, with counter-clockwise rotation, multi-turn travel, and a Zero Stop for a reliable return to baseline settings. Its 34 mm tube, 330.00 mm length, and 728.00 g weight place it in the compact tactical class, while nitrogen filling and a waterproof, fogproof, shockproof build support use in rough weather and on hard-recoiling rifles.

About US Optics

U.S. Optics was founded in 1991 in Buena Park, California, and it established its name in the riflescope market with products aimed at serious precision, tactical, and field shooters. The company is a U.S. manufacturer of riflescopes and shooting optics, and its products are used across competitive, hunting, and defense-shooting applications. One of its notable scope families is the SN-3, and the brand also helped pioneer the category now widely known as the LPVO.

In 2014, U.S. Optics expanded its commercial off-the-shelf offerings with lines such as the SR, ST, MR, LR, and ER series. After acquisition by DRSG, the company moved to Kalispell, Montana, in 2017, then joined ZRO Delta and moved to North Carolina in 2019. Its engineering team is based in Connelly Springs, North Carolina, and the company’s modern lineup continues to focus on robust riflescopes with practical mechanical systems for shooters who dial, hold, and train regularly.

Main Features

• Magnification: 10.00 x
• Objective lens diameter: 42.00 mm
• Exit pupil: 4.20 mm
• Field of view: 3.77 m/100m
• Eye relief: 3.77 mm
• Main tube diameter: 34 mm
• Reticle position: 1. focal plane - FFP
• Illuminated reticle: Yes
• Illumination color: Red
• Daytime-usable illumination: Yes
• Turret type: Tactical
• Turret locking: No
• Zero Stop: Yes
• Turret turns: MT - Multi Turn
• Turret rotation direction: CCW
• Elevation adjustment range: 48.00 mrad / 165.00 MOA
• Windage adjustment range: 28.00 mrad / 96.00 MOA
• Parallax adjustment: Yes - side focus
• Parallax adjustment range: 30 yds - infinity
• Length: 330.00 mm
• Weight: 728.00 g
• Power supply: CR2032
• Filled with: Nitrogen
• Lens coating: Aluminum
• Housing color: Black
• Waterproof: Yes
• Fogproof: Yes
• Shockproof: Yes
• Made in: USA

Warranty

2 years. US Optics states a 2-year warranty for this riflescope.