Does that red dot fit your pistol?
Covers 178 pistol slides, 77 optics and 57 mount systems. 5 are marked “verify” where published sources are thin.
New to red dots? What footprint, plate and co-witness mean
- Layout
- 2 screws, 2 forward recoil lugs
- Screws
- #6-32
- Torque
- 15 in-lb
- Plate in box Holosun 507C X2 on the GLOCK 19 Gen5 MOSMOS Plate 02 ships with the pistol. Buy the optic.Thread 6-32 UNC $300–450
- Direct (cross-fit) Holosun 507K X2 on the SIG Sauer P365XLMounts directly on a cross-compatible cut. Buy the optic.Thread M3 × 0.5 or M4 × 0.7, by slideTorque 15 in-lb $300–450
- Plate Holosun 507C X2 on the GLOCK 43X MOSNeeds a plate from C&H Precision.Thread 4-40 (into the plate's T-nuts) $325–510
- Plate in box Trijicon RMR Type 2 on the Smith & Wesson M&P9 M2.0 Optics Ready (4.25 / 4.6 / 5 in)C.O.R.E. Plate 1 (RMR family) ships with the pistol. Buy the optic. $450–650
- Plate Trijicon RMR Type 2 on the Springfield Armory Hellcat OSPNeeds a plate from C&H Precision.Thread 4-40 (into the plate's T-nuts) $475–710
- Plate Holosun 507K X2 on the SIG Sauer P320 X-CarryNeeds a plate from C&H Precision.Thread M4 $325–510
Every answer includes
- The screw thread
- For each joint, and which bag the screws come from.
- A verify flag
- Where published data is thin or conflicting (5 mount systems), the answer says so and tells you who to ask.
- Screw length from your calipers
- The calculator works from your own readings. No guessed lengths.
- A build sheet
- Parts, torque and install order to print for the bench, from the fit checker.
Popular pistols
All 178 pistolsNo plate neededPlate neededDoesn’t fit
- GLOCK 19 Gen5 MOS No plate needed: 19 Plate needed: 52 Of 77 optics tracked here.
- GLOCK 17 Gen5 MOS No plate needed: 19 Plate needed: 52 Of 77 optics tracked here.
- GLOCK 43X MOS No plate needed: 15 Plate needed: 16 Of 77 optics tracked here.
- GLOCK 48 MOS No plate needed: 15 Plate needed: 16 Of 77 optics tracked here.
- Smith & Wesson M&P9 M2.0 Optics Ready (4.25 / 4.6 / 5 in) No plate needed: 57 Plate needed: 11 Of 77 optics tracked here.
- SIG Sauer P320 X-Carry No plate needed: 10 Plate needed: 36 Of 77 optics tracked here.
- SIG Sauer P365XL No plate needed: 22 Plate needed: 0 Of 77 optics tracked here.
- Springfield Armory Echelon No plate needed: 49 Plate needed: 8 Of 77 optics tracked here.
- Springfield Armory Hellcat OSP No plate needed: 15 Plate needed: 14 Of 77 optics tracked here.
- Walther PDP Full Size (1.0) No plate needed: 0 Plate needed: 59 Of 77 optics tracked here.
- Shadow Systems MR920 No plate needed: 58 Plate needed: 1 Of 77 optics tracked here.
- Ruger RXM No plate needed: 41 Plate needed: 3 Of 77 optics tracked here.
Popular optics
All 77 opticsNo plate neededPlate neededDoesn’t fit
- Trijicon RMR Type 2 No plate needed: 46 Plate needed: 64 Of 178 slides tracked here.
- Trijicon SRO No plate needed: 46 Plate needed: 64 Of 178 slides tracked here.
- Holosun 507C X2 No plate needed: 46 Plate needed: 64 Of 178 slides tracked here.
- Holosun 407C X2 No plate needed: 46 Plate needed: 60 Of 178 slides tracked here.
- Shield Sights RMSc No plate needed: 80 Plate needed: 69 Of 178 slides tracked here.
- Vortex Defender-CCW No plate needed: 80 Plate needed: 69 Of 178 slides tracked here.
- Holosun 507K X2 No plate needed: 59 Plate needed: 82 Of 178 slides tracked here.
- Holosun EPS Carry No plate needed: 59 Plate needed: 80 Of 178 slides tracked here.
- Leupold DeltaPoint Pro No plate needed: 33 Plate needed: 59 Of 178 slides tracked here.
- Aimpoint ACRO P-2 No plate needed: 1 Plate needed: 83 Of 178 slides tracked here.
- Steiner MPS No plate needed: 1 Plate needed: 76 Of 178 slides tracked here.
- Holosun 509T No plate needed: 0 Plate needed: 70 Of 178 slides tracked here.
- Trijicon RMR18 optics
- Shield RMSc15 optics
- Docter / Noblex9 optics
- Holosun K7 optics
- Leupold DeltaPoint Pro7 optics
- Aimpoint ACRO6 optics
- Trijicon RMRcc2 optics
- C-More RTS2 / STS22 optics
- SIG-LOC2 optics
- Holosun 509T1 optic
- Aimpoint Micro1 optic
- Trijicon RCR1 optic
- Aimpoint COA / A-Cut1 optic
- Holosun SCS (MOS)1 optic
- Holosun SCS (320)1 optic
- SIG Romeo1Pro1 optic
- SIG-LOC PRO1 optic
- SIG Romeo21 optic
Why this site exists
Optic Mounting is a personal project by Andrew Terrebonne, a firearms enthusiast who noticed how sparse reliable, up-to-date data and guides on gunsmithing and modification are. Optic Mounting is his personal project to compile what is published about pistol optics and the ways to mount them, in one place and with the source for each figure.
Each answer comes from what the makers publish: the pistol maker for the slide’s cut, the optic maker for its footprint, the plate maker for the plate and its hardware. Every figure sits next to the document it came from and the date it was last checked, and where sources are thin or disagree the page says “verify” instead of guessing. It is a reference, not a gunsmith: check your own maker’s current manual before you mount anything, and see the disclaimer.
Reading rather than looking up? Start with installing a red dot, direct mount or plate, which footprint to buy or red dots for micro-compact pistols, or browse all the guides. How the data is made and checked is on the about page.