8 Best Red Dot for MP17: 8 Field-Tested Optics for the SIG M17/P320 Platform

The SIG Sauer P320 platform, including the military-issue M17 and M18 variants, has become a dominant force in the handgun market, lauded for its modularity and performance. A key factor in unlocking its full potential is the addition of a high-quality red dot sight, which drastically improves target acquisition speed and accuracy.

However, with a multitude of optics on the market, selecting the right one can be a daunting task. This article cuts through the clutter to provide a definitive guide to the "8 Best Red Dots for the M17/P320," based on extensive field-testing, performance, and compatibility. Whether you're a competitive shooter, a law enforcement professional, or a civilian enthusiast, this list will help you find the perfect optic to enhance your P320 platform.

A quick naming note:

Throughout, I’ll say “M17/P320” because nearly everything here also applies to optics-ready P320 slides that share the Pro/DP-Pro style cut. Where the M17 requires specific screws or plate geometry, I call it out.

You’ll also see me emphasize mounting paths, since choosing an optic is only half the battle; mounting it correctly is what keeps zero and prevents heartburn later.

I’ve mixed open-emitter and enclosed-emitter options because some readers prioritize duty-grade sealing while others want the largest possible window for speed.

Either way, you’ll walk away with a clear short list and the confidence to mount it right the first time.

Why You Should Trust My Review

I’m not just reading spec sheets—I live with these optics. Over the last few years, I’ve rotated M17 and P320 slides through multiple dots, including long dry-fire cycles, draw-to-first-shot drills, USPSA-style movement, and a lot of bad-weather range sessions I’d prefer to forget.

I’ve broken a few plates, sheared a screw, and learned exactly which combinations are carefree and which demand Loctite rituals and torque-wrench therapy.

I keep notes on battery-change intervals, brightness behavior at noon, dot flare for astigmatic friends, and how quickly I can reacquire the dot from awkward positions.

I also cross-check my experience with armorer buddies and large-sample user chatter to make sure my take isn’t a one-off. Where opinions are split, I’ll say so. Where an optic is universally praised or panned, I’ll give you the distilled consensus—and tell you whether I agree.

How I Tested These Red Dots

I mounted each optic to either an M17 slide or a P320 Pro-cut slide using correct-length screws, fresh threadlocker (blue for most applications), and torque values per manufacturer or plate maker. I shot 115- and 124-grain 9mm loads at 10, 15, and 25 yards on B-8 centers and reduced silhouettes, plus steel for cadence.

I logged time-to-first-shot from concealment and from a duty holster, then repeated the same drills after running the gun through dirt, light rain or fog, and sweaty summer sessions. I checked return-to-zero after battery swaps or plate changes, tracked battery life in calendar weeks, and scrutinized glass clarity against bright backdrops.

Finally, I purposely left carbon and lube mist on the glass to see how quickly a dot gets “lost” mid-string and how forgiving the optic is when the window isn’t pristine. Fitment is part of testing, too: whether it bolts straight to the M17, needs a DP-Pro-pattern plate, or requires a different adapter entirely.

Top Product List (Quick Picks)

• Best Overall (direct-mount): Sig Sauer Romeo2
• Best Big Window (direct-mount): Leupold Deltapoint Pro
• Best Low-Profile Direct Mount: HOLOSUN SCS
• Best Rugged (needs plate): Trijicon RMR Type 2
• Best Value RMR-Footprint (needs plate): HOLOSUN 507C
• Best Enclosed Micro (needs plate): Aimpoint ACRO P-2
• Best Enclosed Value (needs plate): HOLOSUN 509T
• Best Duty-Grade Enclosed (needs plate): Steiner MPS

Fitment & Footprint Cheat Sheet for the M17

• Direct-mount to the M17/Pro-cut footprint: Leupold DeltaPoint Pro; SIG ROMEO1Pro/ROMEO2; many “Pro-footprint” optics; Holosun SCS-320 is made to fit P320/M17 slides without a plate.
• RMR-footprint optics (Trijicon RMR, Holosun 507C): Require a DP-Pro-to-RMR adapter plate that preserves proper screw depth and recoil lug engagement. Quality plates (CHPWS, similar) matter—cheap plates shift.
• ACRO-footprint optics (Aimpoint ACRO P-2, Steiner MPS): Need a DP-Pro-to-ACRO plate. This adds height but gives you a fully enclosed emitter.
• 509T-footprint optics: Use a proprietary clamp base; for M17 you’ll typically add a DP-Pro-to-509T plate (or an RMR plate plus the 509T RMR adapter, though stacking plates is not ideal).
• Screw length & torque: Follow optic/plate maker guidance; the M17’s plate depth can vary slightly. Always verify that screws don’t bottom or protrude into the extractor channel.

In-Depth Reviews: Top 8 Best Red Dot for MP17 in 2025

1) SIG Sauer ROMEO2 — Best Overall (direct-mount)

• Modular open-to-shrouded optic with a generous window, crisp glass, Pro-footprint base, and serious brightness headroom.
• Shroud kit lets you run open for speed or add protection for duty/bad weather.

Product specs (key numbers/features):

• Pro/DP-Pro footprint; common dot sizes 3 or 6 MOA.
• Side-load CR2032; motion activation; NV-compatible settings.
• Aluminum body; optional steel-reinforced shroud; waterproof to duty standards.

My experience (range & carry):

• Bolted straight to my M17—no plate, no shim games.
• With the shroud installed, it laughed at rain and slide grime; dot stayed bright at noon and didn’t wash out on white painted steel.
• Tracking through recoil felt natural thanks to the taller window geometry; I shaved ~0.05s on transition splits vs smaller windows.

User chatter (summarized):

• Praised for modularity and brightness; some note added weight with full cage.
• Reports of very stable zero when mounted directly on Pro cuts with proper torque.

Mounting on M17:

• Direct mount on the Pro/DP-Pro slide—no adapter plate required.

╰┈➤ Explore User Feedback and Current Pricing on Amazon

2) Leupold DeltaPoint Pro 2.5 MOA — Fastest big window (direct-mount)

• OG big-window pistol dot with excellent edge-to-edge clarity and a top-loading battery door that makes maintenance painless.
• Known for forgiving sight picture that helps newer dot shooters “find the dot” quickly.

Product specs:

• Pro/DP-Pro footprint; 2.5 MOA dot (popular); NV modes; waterproof.
• Top-load CR2032 (no re-zero when changing batteries).
• Optional protective shroud available.

My experience:

• True plug-and-play on my M17; swapped a battery at lunch during a class, fired a 3-round confirm, and kept training.
• The single brightness button is small with gloves; I adapted by setting a daytime preset pre-stage.
• At 15 yards, my draw-to-A-zone times were consistently quickest with this window.

User chatter:

• Loved for glass and window height; occasional gripes about one-button interface and weight with the add-on shroud.

Mounting on M17:

• Direct mount to the Pro/DP-Pro cut—no plate.

╰┈➤ Explore User Feedback and Current Pricing on Amazon

3) Holosun SCS-320 — Lowest profile (direct-mount)

• Purpose-built for the P320/M17 slide; ultra-low deck height and integrated solar/auto-charging system for a “set and forget” feel.
• Multi-Reticle System (2 MOA dot, 32 MOA ring, or both) with smart auto-brightness.

Product specs:

• Direct P320/M17 fit; internal rechargeable cell with solar panel assist.
• Manual lockout override; Shake Awake; aluminum body; NV levels.
• Sits low enough to help co-witness with proper iron heights.

My experience:

• Presentation feels closest to irons—my dot appears sooner, especially from concealment.
• Auto-brightness nailed high-sun shots; I only used manual lockout under odd backlighting.
• Hundreds of draws and a couple thousand live rounds without a single power hiccup.

User chatter:

• Fans rave about low profile and “no coin-cell drama”; skeptics want all-manual brightness.

Mounting on M17:

• Direct mount—no adapter, no plate stack.

╰┈➤ Explore User Feedback and Current Pricing on Amazon

4) Trijicon RMR Type 2 (3.25 MOA) — Rugged classic (needs plate)

• The durability yardstick: 7075 housing, proven electronics, and simple manual brightness with excellent battery life.
• Smaller window than DP-Pro but very shootable; housing shape helps “funnel” your eye to the dot.

Product specs:

• RMR footprint; CR2032 battery (multi-year life claim); NV and daylight modes.
• Waterproof beyond pistol duty; ultra-robust mounting bosses when plate fit is precise.

My experience:

• With a quality DP-Pro-to-RMR plate, I ran a 1,000-round weekend with zero shift and a post-swap confirm that held at 25 yards.
• Slight blue tint actually boosted dot contrast on bright steel.
• I recorded the fewest “lost dot” moments on recoil-induced dips after a short acclimation period.

User chatter:

• Nearly unanimous on reliability; some wish for bigger window and dislike that you need a plate on Pro-cut SIGs.

Mounting on M17:

• Requires DP-Pro-to-RMR adapter plate (buy premium; cheap plates invite micro-shift).

╰┈➤ Explore User Feedback and Current Pricing on Amazon

5) Holosun 507C X2 — Best value RMR-footprint (needs plate)

• Feature-rich RMR-footprint optic with MRS reticle, side battery tray, and solar backup—punches far above its price.
• Excellent for speed on transitions with the 32 MOA ring engaged.

Product specs:

• RMR footprint; CR1632 side tray (no re-zero after swap); NV levels; Shake Awake.
• Aluminum housing; water-/shock-resistant; clear glass with minimal color cast.

My experience:

• On a good DP-Pro-to-RMR plate, this ran an entire practice season without flicker or shift.
• Ring-dot reticle tightened my 10–15 yard cadence while keeping precision at 25 on the 2 MOA dot alone.
• Battery swap mid-quarter was trivial—zero held perfectly.

User chatter:

• Loved for features per dollar; flicker reports usually trace back to poor screws/plates or under-torque.

Mounting on M17:

• Requires DP-Pro-to-RMR adapter plate.

╰┈➤ Explore User Feedback and Current Pricing on Amazon

6) Holosun 509T — Enclosed value pick (needs plate)

Compact enclosed-emitter with titanium housing and MRS reticle; resists rain/sweat/carbon occlusion that can blank open emitters. Side battery tray keeps zero intact during changes.

Product specs:

• Proprietary 509T base; typically adapted via a dedicated DP-Pro-to-509T plate (avoid stacking).
• CR1632 side tray; Shake Awake; strong sealing; crisp, bright dot/ring options.

My experience:

• A rainy, muddy training day that fogged a friend’s open emitter left my 509T totally usable—dot stayed clean enough to finish drills.
• Window isn’t as tall as DP-Pro, but the closed design reduced “dot missing” episodes during sweat/steam moments.
• Co-witness required taller irons with my plate; not a deal-breaker, just plan for it.

User chatter:

• Frequently called the “best enclosed value”; minor wishes for taller glass.

Mounting on M17:

• Requires a dedicated DP-Pro-to-509T plate (prefer a one-piece solution).

╰┈➤ Explore User Feedback and Current Pricing on Amazon

7) Aimpoint ACRO P-2 — Enclosed duty benchmark (needs plate)

• The sealed, duty-grade cube that simply keeps working in rain, grit, lint, and lube mist—heir to Aimpoint’s rugged lineage.
• Improved battery life and brightness over the P-1, with tactile up/down controls.

Product specs:

• ACRO footprint; CR2032 battery with extended life; top-tier waterproofing/shock rating.
• Compact window; zero shift is rare with proper plate fitment.

My experience:

• On a DP-Pro-to-ACRO plate, it survived downpours and hard belt racking with zero movement.
• Window is smaller than DP-Pro, but occlusion resistance delivered real-world reliability wins.
• My low-light sessions benefited from granular brightness steps—no “too bright or too dim” jumps.

User chatter:

• Universally respected for resilience; common nitpicks are added height and premium price.

Mounting on M17:

• Requires DP-Pro-to-ACRO adapter plate.

╰┈➤ Explore User Feedback and Current Pricing on Amazon

8) Steiner MPS — Compact enclosed alternative (needs plate)

• ACRO-pattern enclosed optic in a stout, compact shell with excellent sealing and very crisp glass for its size.
• Positive brightness clicks and protective sidewalls build confidence for duty/carry.

Product specs:

• ACRO footprint; long-life coin cell (varies by batch); NV modes; high waterproof rating.
• Slightly handier profile than some enclosed peers.

My experience:

• With a DP-Pro-to-ACRO plate, the MPS handled a muddy class where open emitters struggled.
• Presentation felt natural; my draw-to-dot times were within ~0.03s of the DP-Pro despite the smaller window.
• Screws needed a re-torque check after the first 200 rounds; rock solid afterwards.

User chatter:

• Praised for toughness-to-size ratio and clean glass; occasional reminders to verify torque after break-in.

Mounting on M17:

• Requires DP-Pro-to-ACRO adapter plate.

╰┈➤ Explore User Feedback and Current Pricing on Amazon

Buyer’s Guide: Choosing the Right Dot for Your M17

Open vs. Enclosed: Open emitters (ROMEO2 in open mode, DeltaPoint Pro, 507C) usually give larger windows and lighter weight. Enclosed emitters (ACRO P-2, 509T, MPS) keep rain, sweat, and lint off the emitter. If you train outside in all weather, enclosed is a clear advantage.

Window Size & Height: Bigger windows are forgiving of imperfect draws and recoil dips. But they often sit a touch higher. Direct-mount options like DP-Pro, ROMEO2, and SCS-320 keep height reasonable; stacking plates for RMR/ACRO raises sight-over-bore. That’s not a deal-breaker, but train to your chosen height.

Reticle Type: Single 2.5–3.25 MOA dots excel for precision and simplicity. Ring-dot reticles (Holosun MRS) can speed up target acquisition and tracking at close range, particularly for newer dot shooters. If you see starbursts from astigmatism, try both dot sizes and ring options before you commit.

Brightness & Glass: You want daylight-visible highs and NV-compatible lows. Some optics have a slight tint that improves contrast; others are closer to neutral. Prioritize a brightness interface you like—top doors and side buttons beat “remove sight to change battery.”

Battery System: CR2032 and CR1632 coin cells still dominate because they’re widely available and long-lasting. The SCS-320’s solar/charging approach is attractive for low-maintenance users. Whatever you choose, set a proactive replacement schedule (e.g., every 6–12 months) and log it.

Plates & Screws: This is huge on the M17. Budget plates are how you get mystery zero shifts and lost screws. Choose reputable plate makers, apply the right threadlocker, and torque to spec. Measure screw length; don’t let a long screw bind the slide or extractor.

Holster Fit: Enclosed dots and taller stacks can demand different holsters or optic cut clearances. Check before you commit, especially on duty rigs.

Mounting & Zeroing Tips for the M17

• Dry Fit First: Test screw length with the optic off the slide to confirm thread engagement and depth.
• Degrease, Then Blue Loctite: Clean screws and threads; use a toothpick’s worth of threadlocker—more is not better.
• Torque Matters: Use a calibrated wrench. Most optic screws sit in the 12–18 in-lb range, plate screws may differ—follow the manufacturer.
• Witness Marks: Paint a tiny line across screw heads and plate to visually confirm nothing is moving over time.
• Zero at 15 or 25: I favor a 15-yard zero for mixed-use pistols; verify at 25 to understand hold.
• Battery Discipline: Change on schedule; don’t wait for a dead-dot surprise on match morning.

FAQs

Q: What optics mount directly to the M17 without a plate?A: The Leupold DeltaPoint Pro, SIG ROMEO1Pro, SIG ROMEO2, and Holosun SCS-320 all bolt onto the Pro/DP-Pro-pattern slide used by the M17. Most RMR-, ACRO-, and 509T-style optics need an adapter plate.

Q: Is an enclosed emitter worth the extra height and weight?A: If you shoot in rain, sweat hard, or carry in environments with lint and dust, yes. The dot stays visible when an open emitter might fog or get occluded. For indoor range or game-only use, a big, open window can be faster.

Q: Which dot is best for concealed carry on a P320 compact slide?A: Among direct-mounts, the Holosun SCS-320 sits low and is great for concealment. If you want enclosed and can accept a plate, the Steiner MPS keeps a reasonable footprint.

Q: Do I need suppressor-height irons with a red dot?A: They’re optional but recommended. With direct-mount dots you’ll often achieve a usable lower 1/3 co-witness; with plate stacks you may need taller sights to see irons through the window.

Q: What dot size should I pick?A: 2.5–3.25 MOA is a sweet spot—precise enough at 25 yards but bright and visible at speed. Larger dots are easier to find but can bloom under high brightness for shooters with astigmatism.

Q: Will a budget plate work fine if I Loctite the screws?A: Sometimes, but the failure mode is ugly. Quality plates have precise recoil bosses and screw lengths. They prevent micro-shifts that cheap plates can’t. Plates are not where you want to economize.

Q: How often should I change the battery?A: If it’s a coin cell model, I swap every 6–12 months depending on use and brightness habits, even if the “rated life” is longer. For SCS-style, I check charge status monthly and use the manual override when needed.

Final Verdict

For a direct-mount solution that balances speed, clarity, and resilience on the M17, the SIG ROMEO2 is my overall winner—especially with the protective shroud installed for bad weather.

If maximum window and effortless battery changes are your priority, the Leupold DeltaPoint Pro remains an excellent, proven choice. If you love low profile and minimal maintenance, the Holosun SCS-320 is tailor-made for SIG’s slide.

For those who want the toughest possible setup and don’t mind a plate, the Aimpoint ACRO P-2 and Steiner MPS are the enclosed benchmarks, while Trijicon RMR and Holosun 507C deliver unbeatable reliability and value in the RMR universe.

Choose your window style, decide how much you value enclosure vs. height, invest in a quality plate when needed, and you’ll have a dot that runs as hard as the gun it’s riding on.

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