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P320 Full Size optic footprint: what red dots fit

SIG P320 Full Size

The P320 Full Size uses a dedicated slide cut, SIG's PRO optic footprint, rather than a plate system. SIG mills the ROMEO1PRO pocket into the slide itself, and because that pattern shares its screw spacing with the Leupold DeltaPoint Pro, both DeltaPoint Pro and ROMEO1PRO class optics seat on the slide with nothing in between. Optic-ready Full Size slides in this family also carry Trijicon RMR and Holosun 507C threaded holes inside the same pocket, so RMR-pattern dots bolt down as well. Footprints outside those two families, Aimpoint ACRO, Holosun 509T, Holosun EPS, and the micro Shield RMSc and Holosun K optics, sit outside what the factory cut accepts. The dovetailed front and rear night sights stay on the slide when the dot goes on.

Two different pockets travel under the P320 name. The current optic-ready Full Size slide is the PRO cut with RMR and Holosun threaded holes added inside it, which is what lets an RMR-pattern dot bolt straight down. Other optic-ready P320 slides carry the ROMEO1PRO pocket alone with no extra holes, which is why plate makers ask owners to count the threaded holes in their own slide before ordering and sell a milling service for the ones that come up short. Buy by the pocket, not by the model name.

Optics that fit
29
No plate needed
29
Plate required
0
Footprints accepted
Trijicon RMR / Holosun 507CLeupold DeltaPoint Pro
Open the interactive checker on the P320 Full Size
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Mounts directly (DeltaPoint Pro / RMR footprint)(29)

These optics carry the DeltaPoint Pro / RMR footprint the slide is cut for. Screws, recoil bosses, and pocket all line up, so they seat on the slide with no plate.

C&H Precision EDC-XL red dot for P320 Full Size
C&H Precision

C&H Precision EDC-XL

$224.99Holosun 507CRMR

RMR-footprint enclosed-emitter carry and duty optic with a larger sight window

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Cyelee Chameleon SRS8 red dot for P320 Full Size
Cyelee Optics

Cyelee Chameleon SRS8

$199.99Holosun 507CRMR

Slim RMR-footprint dot with a large 8 MOA reticle and Cyelee's STIG-RS lens treatment

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Gideon Optics Rock red dot for P320 Full Size
Gideon Optics

Gideon Optics Rock

$199.99RMR

RMR carry optic with 3 MOA dot and 45 MOA circle-dot choices in a shorter housing.

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Osight C (RMR Footprint, Side-Load Battery) red dot for P320 Full Size
Osight

Osight C (RMR Footprint, Side-Load Battery)

$179.99RMR

Open-emitter RMR-footprint red dot with a wide window, side-loading CR1632, and a switchable 3 MOA + 32 MOA MRS reticle.

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C&H Precision COMP red dot for P320 Full Size
C&H Precision

C&H Precision COMP

$299.99Holosun 507CRMR

RMR-footprint open-emitter competition optic with a wide window and multi-reticle options

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C&H Precision COMP Max red dot for P320 Full Size
C&H Precision

C&H Precision COMP Max

$339.95Holosun 507CRMR

Large-window RMR-footprint competition optic with 2 MOA dot and 38 MOA circle options

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Cyelee Wolf EDG red dot for P320 Full Size
Cyelee Optics

Cyelee Wolf EDG

$279.99Holosun 507CRMR

Fully enclosed RMR-footprint pistol dot with a gas-filled housing and side-loading CR1620

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Gideon Optics Granite Competition RMR red dot for P320 Full Size
Gideon Optics

Gideon Optics Granite Competition RMR

$249.99RMR

Large-window RMR competition optic with a 6 MOA red or green dot and 1 MOA adjustments.

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Gideon Optics Omega red dot for P320 Full Size
Gideon Optics

Gideon Optics Omega

$229.99RMR

Large-window RMR optic with 3 MOA dot and 45 MOA circle-dot reticle options.

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Holosun 507C X2 red dot for P320 Full Size
Holosun

Holosun 507C X2

$232.99Holosun 507CRMR

Multi-reticle micro red dot with solar failsafe and shake awake

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Holosun 507C X3 red dot for P320 Full Size
Holosun

Holosun 507C X3

$299.99Holosun 507CRMR

Third-gen multi-reticle pistol dot with photodiode sensor, Solar Failsafe, and RMR footprint

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Holosun 508T X2 red dot for P320 Full Size
Holosun

Holosun 508T X2

$369.99RMR

Titanium-housed open-emitter micro red dot on the RMR footprint with a larger window than the 507C.

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Leupold DeltaPoint Pro red dot for P320 Full Size
Leupold

Leupold DeltaPoint Pro

$449.99DeltaPoint Pro

American-made competition optic with excellent glass clarity

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Osight 3 MOA Green (RMR, Magnetic Charging) red dot for P320 Full Size
Osight

Osight 3 MOA Green (RMR, Magnetic Charging)

$229.99RMR

Original Osight reflex sight on the RMR footprint with a single 3 MOA dot, magnetic charging cover, and aluminum housing.

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Osight SE DPP Enclosed Red Dot red dot for P320 Full Size
Osight

Osight SE DPP Enclosed Red Dot

$239.99DeltaPoint Pro

Enclosed-emitter red dot built on the DeltaPoint Pro footprint, with a 0.91 x 0.71 inch window, switchable 2 MOA dot and 32 MOA circle, and a side-loading CR1620 tray.

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Osight X (RMR Footprint, Magnetic Charging) red dot for P320 Full Size
Osight

Osight X (RMR Footprint, Magnetic Charging)

$229.99RMR

Open-emitter RMR-footprint red dot with a wide window, OAL housing, and a magnetic charging cover for rechargeable operation.

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Osight XE AMRS Enclosed (RMR Footprint) red dot for P320 Full Size
Osight

Osight XE AMRS Enclosed (RMR Footprint)

$249.99RMR

Enclosed-emitter duty red dot on the RMR footprint with the AMRS five-reticle system and a field-swappable side-loading CR1632 battery.

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Osight XR Enclosed (RMR Footprint) red dot for P320 Full Size
Osight

Osight XR Enclosed (RMR Footprint)

$299.99RMR

Duty-rated enclosed-emitter red dot on the RMR footprint with a 2/6+32 MOA multi-reticle system and a magnetic charging cover.

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Riton 3 Tactix PRD 3 red dot for P320 Full Size
Riton Optics

Riton 3 Tactix PRD 3

$329.99RMR

An RMR-footprint open dot with three selectable reticles, a 50,000 hour CR1632, IPX67 sealing, and a Picatinny adapter in the box at $329.99.

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SIG Romeo1 Pro red dot for P320 Full Size
SIG Sauer

SIG Romeo1 Pro

$238.76DeltaPoint Pro

Full-size SIG optic for P320 X-series and similar platforms

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Swampfox Kraken Closed Emitter red dot for P320 Full Size
Swampfox

Swampfox Kraken Closed Emitter

$249.99Holosun 507CRMR

Budget closed-emitter pistol red dot that ships with both RMR and Glock MOS plates

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Vector Optics Frenzy FLEX Titanium red dot for P320 Full Size
Vector Optics

Vector Optics Frenzy FLEX Titanium

$211.65RMR

Titanium RMR-footprint pistol dot with a large aspheric window and selectable reticles

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Vortex Defender-ST Enclosed Solar red dot for P320 Full Size
Vortex

Vortex Defender-ST Enclosed Solar

$319.49DeltaPoint Pro

Closed-emitter DPP-footprint pistol red dot with solar assist and a multi-reticle.

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Vortex Defender-ST Micro Red Dot red dot for P320 Full Size
Vortex

Vortex Defender-ST Micro Red Dot

$249.49DeltaPoint Pro

All-purpose DPP-footprint pistol red dot with top-load CR2032 and Glock MOS plate.

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Vortex Defender-XL Micro Red Dot red dot for P320 Full Size
Vortex

Vortex Defender-XL Micro Red Dot

$339.49DeltaPoint Pro

Large-window pistol red dot on the DeltaPoint Pro footprint with top-load battery

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Holosun SCS-320-GR red dot for P320 Full Size
Holosun

Holosun SCS-320-GR

$399.99DeltaPoint Pro

Solar-powered enclosed pistol optic with direct SIG P320 fit and DPP footprint compatibility

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Trijicon RCR red dot for P320 Full Size
Trijicon

Trijicon RCR

$718.99RMR

Trijicon's enclosed-emitter pistol red dot on the RMR footprint with top-load battery

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Trijicon RMR Type 2 red dot for P320 Full Size
Trijicon

Trijicon RMR Type 2

$588.99RMR

The original pistol red dot that defined the category

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Trijicon SRO Green Dot red dot for P320 Full Size
Trijicon

Trijicon SRO Green Dot

$639.99RMR

Green-LED 2.5 MOA version of the SRO announced May 2026: same wide circular window, RMR footprint, and top-loading CR2032, in black or coyote brown.

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P320 Full Size optic fitment FAQ

What optic footprint does the P320 Full Size use?

The P320 Full Size uses a dedicated slide cut, SIG's PRO optic footprint, rather than a plate system. SIG mills the ROMEO1PRO pocket into the slide itself, and because that pattern shares its screw spacing with the Leupold DeltaPoint Pro, both DeltaPoint Pro and ROMEO1PRO class optics seat on the slide with nothing in between. Optic-ready Full Size slides in this family also carry Trijicon RMR and Holosun 507C threaded holes inside the same pocket, so RMR-pattern dots bolt down as well. Footprints outside those two families, Aimpoint ACRO, Holosun 509T, Holosun EPS, and the micro Shield RMSc and Holosun K optics, sit outside what the factory cut accepts. The dovetailed front and rear night sights stay on the slide when the dot goes on.

Do I need an adapter plate to mount a red dot on the P320 Full Size?

No. The P320 Full Size slide is cut for the DeltaPoint Pro / RMR footprint and DeltaPoint Pro / RMR optics bolt straight to the slide.

Does the Holosun 507C X2 fit a P320 Full Size?

Yes. The Holosun 507C X2 uses the DeltaPoint Pro / RMR footprint that the P320 Full Size slide is cut for, so it bolts straight to the slide with no adapter plate.

Does the Trijicon RMR Type 2 fit a P320 Full Size?

Yes. The Trijicon RMR Type 2 uses the DeltaPoint Pro / RMR footprint that the P320 Full Size slide is cut for, so it bolts straight to the slide with no adapter plate.

Does the Leupold DeltaPoint Pro fit a P320 Full Size?

Yes. The Leupold DeltaPoint Pro uses the DeltaPoint Pro / RMR footprint that the P320 Full Size slide is cut for, so it bolts straight to the slide with no adapter plate.

Will a SIG ROMEO1PRO fit any DeltaPoint Pro cut slide?

Not necessarily. SIG states the ROMEO1PRO fits all SIG SAUER pistols with the PRO RX footprint, and warns that it will not fit every DeltaPoint Pro footprint in the industry because recoil boss dimensions vary between makers. On a P320 Full Size carrying the factory PRO cut it is a direct fit. On another maker's DeltaPoint Pro cut, treat the two footprints as close relatives rather than guaranteed twins.

Is every SIG P320 Full Size optic ready?

No. Optic ready is a SKU-level trait on the P320. SIG lists the current 9mm Full Size, part number 320F-9-BSSP, as optic ready with the PRO footprint, but a slide with no removable cover plate behind the rear sight has no pocket and no threaded holes at all. An adapter cannot create a cut that is not there, so the only paths on such a slide are a milling service or a replacement optic-cut slide.

Keep reading

Optic footprints for other SIG Sauer models

Every pistol with a footprint page