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Sightmark
Overview
The Sightmark Core Shot A-Spec FMS is a robust red dot sight designed for quick target acquisition and enhanced accuracy. Featuring a durable aluminum construction and a red reticle, this optic is optimized for use on firearms equipped with a Picatinny mounting interface. Builders often incorporate this sight into mid-length gas system AR-15 builds chambered in 5.56 NATO, making it a practical choice for a variety of shooting applications.
Specifications
Sightmark Core Shot A-Spec FMS 1x28x18mm Red Dot Sight - SM26017
Available Merchants(6)
Prices checked
Price Alert
October 2026 on GunPartPicker
Sightmark Core Shot A-Spec FMS 1x28x18mm Red Dot Sight - SM26017 ranked #25 of the 220 optics builders added on GunPartPicker in October 2026, behind the EOTECH HHSVIII XPS3 WITH G33 MAG TAN, with about 1 in every 125 optics added to builds. Down from #18 in September. Builds with this optic are mostly chambered in 5.56 NATO (76%, then .223 Wylde 9%), split between mid-length (56%) and carbine-length (25%) gas systems, and mostly AR-15 (91%).
Availability is good: it was in stock at one retailer or another nearly every day in October 2026, but today none of the 6 retailers we track has it in stock right now. Prices barely moved in October 2026, holding around $129.97, so there haven't been real sales lately. Listed prices start at $129.97 at Classic Firearms for when it comes back.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 37 retailers
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Frequently Built With
The part most often added in each category by hundreds of builds that include this one
Smith & Wesson M&P15 Complete Lower 5.56x45mm/.223 Remington, Black - 812002
Geissele Automatics AR-15 SSA-E X Lightning Bow Trigger
Hogue OverMolded Reinforced Polymer Collapsible Buttstock, Olive Drab Green - 15250
Bravo Company Manufacturing 5.56 NATO Mid-Length Bhf AR-15 Barreled Upper - MCMR-15 - 16"
Aero Precision AR-15 Breach Charging Handle Ambidextrous Small Levers
NCSTAR PRO Series Sight Front/Rear Flip Up, Black - VMARFLC
Build Configuration Breakdown
Aggregated and anonymized data showing how builders use this product
PlatformBased on real build data showing which platform (AR-15, AR-10, AR-9) builders pair with this product.
CaliberBased on real build data showing which calibers builders choose alongside this product.
Gas SystemBased on real build data showing which gas system lengths builders use with this product.
Builds Featuring This Part
See all builds →Builds in the community that include the Sightmark Core Shot A-Spec FMS 1x28x18mm Red Dot Sight - SM26017
| Build | Parts | Total |
|---|---|---|
 | 28 | $2047.45 |
 | 15 | $1147.21 |
 | 8 | $1333.55 |
 | 14 | $934.26 |
 | 24 | $5109.60 |
 | 12 | $3451.07 |
 | 29 | $2033.42 |
 | 18 | $2423.82 |
 | 14 | $1008.42 |
| 27 | $1840.50 |
 | 11 | $2365.91 |
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