Red Dot Footprint Chart and Fit Checker: Which Optic Fits Your Pistol

Last updated October 2026 · By Nick Hall, who has a drawer full of adapter plates that fit nothing he owns

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Quick Answer: A red dot footprint is the screw spacing and recoil boss pattern on the bottom of the optic. Your slide has to match it, either cut for it directly or through an adapter plate. The big ones are the Trijicon RMR, the Shield RMSc, Holosun K, the Leupold DeltaPoint Pro and the Aimpoint ACRO. Pick your pistol in the checker below and it tells you which optics bolt straight on, which need a plate, and which ones don’t fit.

I built this because the footprint question is where most red dot money gets wasted. The optic is fine, the pistol is fine, and they don’t go together. The checker covers 48 optics-ready pistols and 62 pistol red dots, and every answer comes from the pistol maker’s or the optic maker’s own page. Where a maker says “check first” or the two makers disagree, the checker says so too instead of guessing.

Table of Contents

Red Dot Fit Checker

Green means the maker says it bolts straight to the slide. Blue means it mounts with a plate, and the checker names the plate and whether it’s in the box. Purple means the adapter comes in the optic’s own box. Yellow means one of the makers adds a warning you should read before you order.

Red Dot Footprint Chart

Here’s the same data as one chart, sorted by footprint. If you already know your slide’s cut, find it in the first column and the second column is your shopping list.

Footprint	Optics that use it	Pistols cut for it (direct)	Pistols that take it with a plate
Trijicon RMR	Trijicon RMR Type 2, Trijicon RMR HD, Trijicon SRO, Trijicon RCR, Holosun HS407C X2, Holosun HS507C X2, Holosun HS507C X3, Holosun HE508T X2, Holosun HS507COMP, Swampfox Kingslayer, Swampfox Justice II, Meprolight MPO-F, Meprolight MPO PRO-F	Springfield Armory Echelon (all models), Canik METE SFx, Canik METE SFT, Ruger RXM	GLOCK G17 Gen6, GLOCK G19 Gen6, GLOCK G45 Gen6, GLOCK G17 Gen5 MOS, GLOCK G19 Gen5 MOS, GLOCK G45 MOS, GLOCK G34 Gen5 MOS, GLOCK G47 MOS, GLOCK G26 Gen5 MOS, GLOCK G20 Gen5 MOS, GLOCK G21 Gen5 MOS, GLOCK G40 Gen4 MOS, Springfield Armory XD-M Elite OSP, Springfield Armory 1911 DS Prodigy AOS, Canik TP9 SFx, Walther PDP (Gen1 flat-bottom cut), FN FN 509 / 510 / 545 MRD and Tactical, Taurus G3 / G3c T.O.R.O., Staccato P (optic ready), Staccato C2 / CS (optic ready)
Shield RMSc	Holosun EPS Core, SIG Sauer ROMEO-X Compact, SIG Sauer ROMEO-X Enclosed Compact, SIG Sauer ROMEOZero, SIG Sauer ROMEOZero Elite, Shield RMSc, Shield SMSc, Shield RMSw, Shield AMSc, Shield RMSsc, Swampfox Sentinel II, Vortex Defender-CCW, Vortex Defender-CCW Enclosed Solar, Burris FastFire C, Crimson Trace CTS-1550, Crimson Trace CT RAD Micro Pro, Meprolight MPO-S, Meprolight MPO PRO-S	GLOCK G43X MOS, GLOCK G48 MOS, GLOCK G43X MOS-K, GLOCK G48 MOS-K, SIG Sauer P365 (optic ready), SIG Sauer P365X, SIG Sauer P365XL, SIG Sauer P365-XMACRO COMP, SIG Sauer P365-380, SIG Sauer P322, Smith & Wesson M&P Shield X, Smith & Wesson CSX E-Series, Springfield Armory Hellcat OSP, Springfield Armory Echelon (all models), Canik TP9 Elite SC, Canik METE SFx, Canik METE SFT, Ruger RXM, FN FN Reflex MRD, Taurus GX4 T.O.R.O. / GX4XL T.O.R.O.	Springfield Armory XD-M Elite OSP, Springfield Armory 1911 DS Prodigy AOS, Staccato C2 / CS (optic ready)
Holosun K	Holosun HS407K X2, Holosun HS507K X2, Holosun EPS, Holosun EPS Carry, Holosun SCS Carry	GLOCK G43X MOS-K, GLOCK G48 MOS-K, Smith & Wesson M&P Shield X, Smith & Wesson CSX E-Series, Springfield Armory Echelon (all models), FN FN Reflex MRD, Taurus GX4 T.O.R.O. / GX4XL T.O.R.O.	Springfield Armory XD-M Elite OSP, Springfield Armory 1911 DS Prodigy AOS
Leupold DeltaPoint Pro	Holosun SCS-320, Leupold DeltaPoint Pro, Vortex Defender-ST, Vortex Defender-XL, Vortex Venom Enclosed Micro	Springfield Armory Echelon (all models), Ruger RXM	GLOCK G17 Gen6, GLOCK G19 Gen6, GLOCK G45 Gen6, GLOCK G17 Gen5 MOS, GLOCK G19 Gen5 MOS, GLOCK G45 MOS, GLOCK G34 Gen5 MOS, GLOCK G47 MOS, GLOCK G26 Gen5 MOS, GLOCK G20 Gen5 MOS, GLOCK G21 Gen5 MOS, GLOCK G40 Gen4 MOS, Smith & Wesson M&P9 M2.0 Optics Ready (C.O.R.E.), Springfield Armory XD-M Elite OSP, Springfield Armory 1911 DS Prodigy AOS, Canik TP9 SFx, Walther PDP (Gen1 flat-bottom cut), FN FN 509 / 510 / 545 MRD and Tactical, Taurus G3 / G3c T.O.R.O., Staccato P (optic ready), Staccato C2 / CS (optic ready)
SIG PRO (ROMEO1PRO)	SIG Sauer ROMEO1PRO, SIG Sauer ROMEO2, SIG Sauer ROMEO-X Pro, SIG Sauer ROMEO-X Enclosed Pro	SIG Sauer P320-M18, SIG Sauer P320 XFIVE LEGION, SIG Sauer P229 LEGION RXP Compact	None listed
Aimpoint ACRO	Aimpoint ACRO P-2, Aimpoint ACRO C-2, Burris FastFire E, Steiner MPS, Steiner MPS 2.0	Walther PDP F-Series Professional ACRO	Springfield Armory Echelon (all models), Springfield Armory 1911 DS Prodigy AOS, Canik TP9 SFx, Walther PDP (Gen1 flat-bottom cut), Staccato P (optic ready), Staccato C2 / CS (optic ready)
Docter	Burris FastFire 4, Crimson Trace CTS-1250, Crimson Trace CT RAD Pro	None listed	GLOCK G17 Gen5 MOS, GLOCK G19 Gen5 MOS, GLOCK G45 MOS, GLOCK G34 Gen5 MOS, GLOCK G47 MOS, GLOCK G26 Gen5 MOS, GLOCK G20 Gen5 MOS, GLOCK G21 Gen5 MOS, GLOCK G40 Gen4 MOS, Springfield Armory Echelon (all models), Springfield Armory XD-M Elite OSP, Canik TP9 SFx, Walther PDP (Gen1 flat-bottom cut), Walther PDP (Gen2 lug-bottom cut), FN FN 509 / 510 / 545 MRD and Tactical, Taurus G3 / G3c T.O.R.O.
Trijicon RMRcc	Trijicon RMRcc	None listed	Taurus GX4 T.O.R.O. / GX4XL T.O.R.O., Staccato P (optic ready), Staccato C2 / CS (optic ready)
Holosun 509T	Holosun HE509T X2	None listed	Springfield Armory 1911 DS Prodigy AOS, Staccato P (optic ready), Staccato C2 / CS (optic ready)
Aimpoint A-CUT	Aimpoint COA	None listed	None listed
SIG-LOC	SIG Sauer ROMEO-X SIG-LOC Compact	None listed	None listed

The Footprints, One by One

Trijicon RMR

The RMR pattern is the closest thing pistol optics have to a standard. Trijicon’s RMR Type 2, RMR HD, SRO and RCR all use it, and so do Holosun’s 407C, 507C and 508T, the Swampfox Kingslayer and Justice II, and Meprolight’s MPO-F. It’s the plate that ships in the box with a GLOCK MOS pistol and the one most optics-ready full-size guns take. Our Trijicon RMR review covers the optic itself.

One catch: Trijicon specifies its own mounting kits for the RMR and SRO on GLOCK MOS, Springfield OSP, Walther PDP and HK VP9 slides. Same footprint, different plate.

Shield RMSc

This is the micro-compact footprint. The SIG P365 family, the Springfield Hellcat OSP, GLOCK’s Slimline MOS cut on the G43X and G48, the Canik TP9 Elite SC and the Taurus GX4 T.O.R.O. all take it direct. Optics on this pattern include the Shield RMSc, SMSc and RMSw, the SIG ROMEOZero and ROMEO-X Compact, the Holosun EPS Core, the Swampfox Sentinel II and the Vortex Defender-CCW.

SIG’s own note on the ROMEOZero is worth knowing: it uses M3 screws on a P365 and M4 screws on other RMSc cuts. Same pattern, different thread. If you’re carrying a P365, our P365 models explained guide sorts out which P365 you actually have.

Holosun K Is Not the Same as RMSc

This is the one that catches people. Holosun’s 407K and 507K, the full-size EPS and the EPS Carry all use the Holosun K footprint. It’s close to RMSc, but Holosun ships an RMSc-to-K adapter plate with the EPS Carry, and you don’t ship an adapter between two patterns that are the same. GLOCK makes the same point: its newer Slimline MOS-K cut “is modified to accept either Holosun K or RMSc footprints,” which only makes sense if the old cut took one and not the other.

So when a pistol maker writes “RMSc/K” (S&W on the Shield X, Taurus on the GX4, FN on the Reflex), a K optic goes straight on. When the maker only says RMSc, the checker flags K optics as check first.

Leupold DeltaPoint Pro and the SIG PRO Trap

The DeltaPoint Pro pattern takes the Leupold DPP, the Vortex Defender-ST and Defender-XL and the newer enclosed Vortex Venom. SIG’s ROMEO1PRO and ROMEO2 look like they belong here, and SIG’s own marketing for the ROMEO-X Pro calls it a DPP footprint. But SIG’s ROMEO1PRO page also says its PRO pattern “will not fit all DeltaPoint PRO footprints in the industry, due to variances in recoil boss dimensions.” I go with the specific warning over the marketing line, so the checker keeps SIG PRO separate and flags DPP-to-PRO swaps.

Aimpoint ACRO and the New A-CUT

The ACRO is the enclosed duty footprint. The Aimpoint ACRO P-2 and C-2, the Steiner MPS and MPS 2.0 and the Burris FastFire E all use it. Hardly any pistol is cut for it direct. Walther’s PDP F-Series Professional ACRO is, and most others take it with a plate you buy separately.

Aimpoint’s newer COA uses a different interface it calls A-CUT. It is not an ACRO, so don’t buy an ACRO plate for it.

Docter, RMRcc and 509T

The Docter pattern is the old open-reflex footprint used by the Burris FastFire 4, the Crimson Trace CTS-1250 and the CT RAD Pro. GLOCK, Canik, Taurus and others still make a plate for it. The Trijicon RMRcc has its own footprint despite the name, and Trijicon sells RMRcc-specific plates. The Holosun 509T has its own pattern too, and fits RMR slides only through the adapter Holosun includes.

Plate Systems: GLOCK MOS, Gen6 and the Rest

GLOCK’s Gen6 pistols dropped MOS. The G17, G19 and G45 Gen6 come optic-ready with three plates in the box: 02 for Trijicon, Holosun (except the 509) and Ameriglo, 03 for C-More, and 04 for Leupold, EOTech and the Vortex Defender. GLOCK sells the spare plate set as “G17, G45, G19 Gen6 Only,” so your old MOS plates aren’t listed as fitting. GLOCK lists no Gen6 plate for the Shield RMSc, Docter or Aimpoint ACRO. If you’re weighing up the new gun, our Glock 19 Gen 6 review and G17 vs G19 Gen 6 comparison cover the rest of what changed.

A Gen5 MOS pistol ships with one plate, the one for Trijicon, Ameriglo and Holosun. Plates 01 (Docter-pattern), 03 (C-More) and 04 (Leupold, EOTech and Shield) are extra. The big-frame MOS guns like the G20 and G21 use their own numbers, 05 to 08.

Two other systems need a closer look. Walther cut the PDP two ways, a flat-bottomed first-generation cut and a second-generation cut with lugs, and its plates only fit one or the other. And Canik changed the METE SFx and SFT mid-run: guns after serial 26BY00001 (SFx) or 25CC08376 (SFT) take a full-size RMR, and earlier guns take the RMRcc. The checker asks you to check both.

Five Checks Before You Order

• Match the footprint name, then read the warnings. Two optics can share a footprint name and still have different recoil bosses or screw threads. The SIG PRO and ROMEOZero notes above are both real examples.
• Check what came in your box. GLOCK Gen6 ships three plates, Gen5 MOS ships one, Walther ships none, and Canik’s own pages disagree on how many come with a TP9 SFx.
• Use the right screws. FN issued a 2025 service bulletin on the Reflex MRD after screws that were too long hit the firing-pin block, and FN now says to use only FN-supplied screws. Too-long screws can bind the striker on any small slide.
• Check your serial or cut generation. Canik’s METE and Walther’s PDP both changed partway through production.
• Torque it and use thread locker. CZ’s P-10 manual calls for thread glue and 1.3 Nm on the plate screws. Follow your maker’s number.

If you haven’t picked the optic yet, start with our best red dots for pistols, or the best red dot for concealed carry if it’s going on a carry gun. Still shopping for the pistol? The best optics-ready pistols guide is the place to start.

Where to Buy the Most Common Footprints

These are the optics I’d look at first for each of the main footprints, with live prices from the retailers we track.

Trijicon RMR Type 2

The original RMR footprint and still the toughest open emitter on a full-size gun.

Holosun 507C X2

Same RMR footprint for less money, so it drops onto the same plate as a Trijicon.

Shield RMSc

The optic the micro-compact footprint is named after. It goes straight on a P365 or Hellcat OSP.

Holosun 507K X2

The K footprint. It goes direct on a Shield X, GX4, Reflex or MOS-K slide.

Leupold DeltaPoint Pro

The DPP footprint, and the big window people buy it for.

Aimpoint ACRO P-2

The enclosed ACRO footprint. Check the checker for which plate your pistol needs.

How I Built This

Every pistol and optic in the checker was read from the maker’s own website, spec sheet or owner’s manual on October 27, 2026. I kept the exact wording behind each answer and checked it word for word against the saved page. Where makers contradict themselves, I go with the specific warning over the general marketing line. Where nobody says, the checker says “not listed” instead of guessing. HK’s website blocks automated reading, so the VP9 entry uses only what Trijicon and Holosun publish about it. If your pistol or optic isn’t here yet, it’s because I couldn’t find a maker statement I trusted. More are on the way. For the bigger picture on sight types, see our types of gun sights guide.

FAQ: Red Dot Footprints