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Choose a red dot sight that fits your firearm

By the Plain Prepper editors. Updated 2026-10-18.

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Quick answer

A red dot sight puts an illuminated dot on a 1x lens; Bushnell lists unlimited eye relief on these sights for fast shots at imperfect angles. Start with the mount: closed-tube sights like Bushnell's TRS-25 and TRS-26 clamp to a Picatinny rail, while the open RXS-100 fits the DeltaPoint Pro footprint and includes a Weaver-style mount. Then compare dot size (3 MOA on the TRS models, 4 MOA on the RXS-100), battery life (up to 5,000 hours, or 50,000 on the TRS-26) and water rating.

Closed tube or open reflex

Bushnell lists the TRS-25, TRS-25 HiRise and TRS-26 as closed reflex sights: the lens and emitter sit inside a sealed tube. It lists the RXS-100 as an open reflex sight, which it says mounts on pistols, AR-style rifles and shotguns.

Bushnell lists the RXS-100 at 1.3 oz, the TRS-25 at 3.7 oz, and the TRS-25 HiRise and TRS-26 at 6 oz each.

Mount and height

Match the sight's base to what is on your firearm. Bushnell lists a Picatinny mount on the TRS-25, a High-Rise Picatinny mount on the TRS-25 HiRise, and a Picatinny High-Rise mount on the TRS-26 that it also calls T1 compatible. The RXS-100 mounts directly to the DeltaPoint Pro standard footprint and comes with a Weaver-style low-rise mount.

Check your firearm's manual and the mount footprint before buying. This guide does not cover milling slides or any firearm alteration.

Dot size and brightness

Dot size is given in MOA (minutes of angle); a smaller number is a smaller dot. Bushnell lists a 3 MOA red dot on the TRS-25, HiRise and TRS-26, and a 4 MOA dot on the RXS-100.

It lists 11 brightness settings on the TRS-25 and HiRise, 10 on the TRS-26 and 8 on the RXS-100.

Battery life and auto-off

All four run on a CR2032 coin cell. Bushnell lists up to 5,000 hours on the TRS-25, HiRise and RXS-100, and up to 50,000 hours on the TRS-26. The TRS-26 has a user-selectable auto-off after 12 hours without a button press; the RXS-100 also shuts off after 12 hours without a button press. Bushnell lists no auto-off on the TRS-25 or HiRise, so turn those off yourself.

Bushnell says the RXS-100's battery can be changed without removing the sight, so you keep your zero.

Water rating and toughness

Bushnell lists IPX7 on the TRS-26 and IPX5 on the TRS-25 and HiRise. Its feature text for the TRS models also describes O-ring sealing and nitrogen fog-proofing; go by the IPX rating when comparing. Bushnell describes the RXS-100's housing as aircraft-grade extruded aluminum built to handle recoil, including from pistols.

Adjustments and zeroing

Bushnell lists 1 MOA per click on all four, 80 MOA of windage and elevation on the TRS-25 and HiRise, and 100 MOA on the TRS-26 and RXS-100, with a 50-yard minimum parallax distance.

Follow the sight's manual to zero it, and do it at a range with the firearm unloaded while you mount and adjust.

Safety

Mount and adjust a sight only with the firearm unloaded and pointed in a safe direction, keep your finger off the trigger until you intend to shoot, and know what is beyond your target, as NSSF advises. Project ChildSafe says firearms should be unloaded when not in use. Follow local laws.

What to look for when you buy

Questions people ask

What does MOA mean on a red dot?

It is the dot size in minutes of angle. Bushnell's TRS models use a 3 MOA dot and the RXS-100 a 4 MOA dot.

How long do red dot batteries last?

Bushnell lists up to 5,000 hours on the TRS-25 and RXS-100 and up to 50,000 hours on the TRS-26, all on a CR2032.

Will a red dot fit my pistol?

Only if the firearm or mount matches the sight's footprint. Bushnell lists the RXS-100 for the DeltaPoint Pro footprint and includes a Weaver-style mount. Check your firearm's manual.

What does unlimited eye relief mean?

Bushnell lists unlimited eye relief on these sights and says it allows fast shots at imperfect angles.

Sources

• Trophy TRS-25 Red Dot Sight (BU-731303) (bushnell.com), Bushnell
• AR Optics TRS-26 Red Dot Sight (BU-AR71XRD) (bushnell.com), Bushnell
• RXS-100 Reflex Sight (BU-RXS100) (bushnell.com), Bushnell
• AR Optics TRS-25 HiRise Red Dot Sight (BU-AR731306) (bushnell.com), Bushnell
• Rules of Firearms Safety (nssf.org), NSSF
• Ten Tips for Firearm Safety in Your Home (projectchildsafe.org), Project ChildSafe (NSSF)

Sources checked 2026-10-18.