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Duty Arms Index

Pistol optic evaluation memo: Holosun 509T vs SIG SAUER ROMEO-X

Prepared Oct 11, 2026 from Duty Arms Index; agency data as of Oct 11, 2026. Specs as published by each maker, checked Oct 11, 2026.

Live page, sources and updates
Version comparedHolosun 509THolosun HE509T-RD X2SIG SAUER ROMEO-XSIG SAUER ROMEO-X PRO
Mounting footprint509T Footprint [1]PRO [2]
EmitterFully enclosed emitter [1]Not published
Mounting notes (maker's)RMR to 509T Adapter Plate [1]Not published
Reticle / dot size2 MOA Dot & 32 MOA Circle [1]3 MOA, 6 MOA, CIRCLE DOT [2]
Reticle colourNot publishedNot published
Window size0.66" x 0.9" [1]24 mm [2]
Brightness settings8 Daylight & 4 [1]12 Daytime 3 Night Vision [2]
Night-vision settingsNot publishedNot published
BatteryCR1632 [1](1) CR1632 [2]
Battery life (maker's stated)50,000 Hours [1]20000 hrs [2]
Battery accessNot publishedNot published
Auto-on / auto-brightnessShake Awake Technology [1]Not published
Dimensions1.6" x 1.16" x 1.13" [1]Height 0.94 in [23.88 mm]; Overall Length 1.83 in [46.48 mm] [2]
Weight1.27 oz [1]Not published
Housing material7075 T6 Titanium [1]Not published
Water rating (maker's stated)IP67 [1]Not published
Maker list priceNot publishedNot published
Agencies issuing (current entry)17 of 105 agencies with a sourced pistol optic1 of 105 agencies with a sourced pistol optic
Most common host pistolGlock G45 Gen5 MOS (5)SIG SAUER P320 (1)

Notices

No recalls, safety statements or agency actions on file for either model.

Sources

  1. [1] Holosun HE509T-RD X2. Holosun. Accessed Oct 11, 2026. https://www.holosun.com/products/he509t-x2-rd (archive: https://web.archive.org/web/2026/https://www.holosun.com/products/he509t-x2-rd)
  2. [2] ROMEO-X PRO. SIG SAUER. Accessed Oct 11, 2026. https://www.sigsauer.com/romeo-x-pro.html (archived maker page, captured Oct 2, 2026: https://web.archive.org/web/20261002153250/https://www.sigsauer.com/romeo-x-pro.html)

Not a recommendation. Duty Arms Index records what agencies issue and what makers publish; it does not test, rate or endorse equipment. Specs are copied as published by each maker for the version named and can change without notice; output, battery-life and water figures are the maker's own and may use different test conditions. Verify with the manufacturer before purchase or policy decisions. Agency counts cover agencies with a sourced entry in the index, not all US agencies.

https://dutyarmsindex.com/compare/pistol-optics/holosun-509t-vs-sig-romeo-x