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What red dots fit the Rock Island Armory STK100?

Page last updated . Data compiled September 2026 by Andrew Terrebonne.

22 of the 77 optics tracked here mount to this slide, and 22 of those need no adapter plate. This slide uses RMSc-pattern direct cut.

No plate neededPlate neededDoesn’t fit

Mount systemRMSc-pattern direct cut
Optics that fit22 of 77
No plate needed22

New to red dots? What footprint, plate, co-witness and the rest mean

Screw thread not on fileNo screw thread is on file for this slide, and slim cuts from different makers are tapped M3, M4 or #6-32. Start each screw by hand. If it binds, stop and check the pistol's manual or ask the maker.

Cheapest ways to mount it

Cheapest overall, and with no plate$60–150SIG Sauer ROMEOZerodirect — no adapterBuild sheet
Cheapest enclosed emitter$300–450Holosun EPS-COREdirect — no adapterBuild sheet
Same slide cutMakers with the same cut: Smith & Wesson M&P 22 Magnum, Smith & Wesson CSX E-Series Optics Ready, Springfield Armory XD-S Mod.2 OSP, Canik METE MC9 / MC9L, FN Reflex MRD, Beretta APX A1 Carry, Ruger MAX-9 and Ruger Ruger-5.7 Optics Ready, and 15 more. The optics that fit are the same; the screw thread and the sights can differ, and each page says what is on file.
How this slide mounts an opticMilled for the Shield RMSc pattern. No plate is needed. Holosun K optics bolt on directly as well.

Every optic, and how it mounts

ItemFootprintHow it mountsCost to mount
Direct — 15
Crimson Trace CTS-1550Build sheetShield RMScdirect — no adapter$150–300
Holosun EPS-CORE EnclosedBuild sheetShield RMScdirect — no adapter$300–450
JP Enterprises JPointBuild sheetShield RMScdirect — no adapter$150–300
Olight Osight SBuild sheetShield RMScdirect — no adapter$60–150
Primary Arms Classic 21 mm MicroBuild sheetShield RMScdirect — no adapter$60–150
Riton 3 TACTIX MPRD 2Build sheetShield RMScdirect — no adapter$150–300
Shield Sights RMS2Build sheetShield RMScdirect — no adapter$150–300
Shield Sights RMScBuild sheetShield RMScdirect — no adapter$150–300
SIG Sauer ROMEO-X CompactBuild sheetShield RMScdirect — no adapter$150–300
SIG Sauer ROMEOZeroBuild sheetShield RMScdirect — no adapter$60–150
SIG Sauer ROMEOZero EliteBuild sheetShield RMScdirect — no adapter$150–300
Springfield Armory Hex WaspBuild sheetShield RMScdirect — no adapter$150–300
Swampfox Sentinel IIBuild sheetShield RMScdirect — no adapter$60–150
Viridian RFX35Build sheetShield RMScdirect — no adapter$60–150
Vortex Defender-CCWBuild sheetShield RMScdirect — no adapter$150–300
Direct (cross-fit) — 7
Holosun 407K X2Build sheetHolosun Kdirect — no adapter$150–300
Holosun 507K X2Build sheetHolosun Kdirect — no adapter$300–450
Holosun 507K X3 / 407K X3Build sheetHolosun Kdirect — no adapter$300–450
Holosun EPS EnclosedBuild sheetHolosun Kdirect — no adapter$300–450
Holosun EPS Carry EnclosedBuild sheetHolosun Kdirect — no adapter$300–450
Holosun SCS Carry EnclosedBuild sheetHolosun Kdirect — no adapter$300–450
Olight Osight KBuild sheetHolosun Kdirect — no adapter$60–150
No fit — 55
ADE Delta ProTrijicon RMRno known route—
ADE NUWAcc ProTrijicon RMRccno known route—
Aimpoint ACRO C-2 EnclosedAimpoint ACROno known route—
Aimpoint ACRO P-1 EnclosedAimpoint ACROno known route—
Aimpoint ACRO P-2 EnclosedAimpoint ACROno known route—
Aimpoint COA EnclosedAimpoint COA / A-Cutno known route—
Aimpoint Micro T-2 EnclosedAimpoint Microno known route—
Ameriglo HavenTrijicon RMRno known route—
Burris FastFire 3Docter / Noblexno known route—
Burris FastFire 4Docter / Noblexno known route—
Bushnell RXS-100Leupold DeltaPoint Prono known route—
C-More RTS2C-More RTS2 / STS2no known route—
C-More STS2C-More RTS2 / STS2no known route—
C&H Precision CompTrijicon RMRno known route—
Cyelee Cat / WolfTrijicon RMRno known route—
EOTECH EFLX MiniLeupold DeltaPoint Prono known route—
Holosun 407C X2Trijicon RMRno known route—
Holosun 407COMPTrijicon RMRno known route—
Holosun 507-PromaxTrijicon RMRno known route—
Holosun 507C X2Trijicon RMRno known route—
Holosun 507C X3 / 407C X3Trijicon RMRno known route—
Holosun 507COMPTrijicon RMRno known route—
Holosun 508T X2Trijicon RMRno known route—
Holosun 509T EnclosedHolosun 509Tno known route—
Holosun SCS 320 EnclosedHolosun SCS (320)no known route—
Holosun SCS MOS EnclosedHolosun SCS (MOS)no known route—
Leapers UTG OP3 MicroDocter / Noblexno known route—
Leupold DeltaPoint ProLeupold DeltaPoint Prono known route—
Lucid Optics E7 EnclosedAimpoint ACROno known route—
Meopta MeoSight IVDocter / Noblexno known route—
Meprolight MPO-DFTrijicon RMRno known route—
Noblex Sight III / Docter Sight CDocter / Noblexno known route—
Riton 3 TACTIX PRDTrijicon RMRno known route—
SIG Sauer ROMEO-X EnclosedSIG-LOCno known route—
SIG Sauer ROMEO-X ProLeupold DeltaPoint Prono known route—
SIG Sauer ROMEO-X SIG-LOC Compact EnclosedSIG-LOCno known route—
SIG Sauer ROMEO-X SIG-LOC Pro EnclosedSIG-LOC PROno known route—
SIG Sauer ROMEO1PROSIG Romeo1Prono known route—
SIG Sauer ROMEO2 EnclosedSIG Romeo2no known route—
Sightmark Mini Shot A-SpecDocter / Noblexno known route—
Springfield Armory Hex DragonflyDocter / Noblexno known route—
Steiner MPS EnclosedAimpoint ACROno known route—
Swampfox Justice IITrijicon RMRno known route—
Swampfox Liberty IITrijicon RMRno known route—
Trijicon RCR EnclosedTrijicon RCRno known route—
Trijicon RMR HDTrijicon RMRno known route—
Trijicon RMR Type 2Trijicon RMRno known route—
Trijicon RMRccTrijicon RMRccno known route—
Trijicon SROTrijicon RMRno known route—
Viridian RFX45 EnclosedAimpoint ACROno known route—
Vortex Defender-SLLeupold DeltaPoint Prono known route—
Vortex Defender-STLeupold DeltaPoint Prono known route—
Vortex Defender-XLLeupold DeltaPoint Prono known route—
Vortex VenomDocter / Noblexno known route—
Vortex ViperDocter / Noblexno known route—
GuidesShield RMSc vs Holosun K: which optic fits which cut · Suppressor-height sights: will your irons co-witness? · Installing a red dot: what the makers say

Check a specific pairing

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