Sig Sauer P320 Compact .45 ACP 3.9″ Nitron Black Night Sights
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About this product
The Sig Sauer P320 Compact in .45 ACP is a striker-fired semi-auto that bridges the gap between full-size duty guns and subcompact carry pieces. With a 3.9-inch barrel and SIGLITE night sights, this Nitron-finished pistol gives you .45-level stopping power in a package that still fits a hip holster or nightstand drawer. It ships with two 9-round magazines and a 1913 Picatinny rail, so you get modularity and low-light readiness right out of the box.
| Manufacturer | Sig Sauer |
|---|---|
| Model | P320 Compact |
| Material | Stainless steel slide with Nitron finish, polymer grip module |
| Compatibility | P320 holsters and grip modules (Compact size) |
| Finish | Nitron black |
| Weight | 28.3 oz (unloaded, per manufacturer specs) |
| Condition | New |
Key Features
- SIGLITE Night Sights – Why it matters: Tritium inserts let you acquire your front sight in total darkness, so this .45 stays combat-effective after sundown without needing a light.
- 3.9-inch Cold Hammer-Forged Barrel – Why it matters: Sig’s hammer-forged barrels hold up to thousands of rounds of .45 ACP, and the 3.9-inch length balances concealability with full-power ballistics.
- Striker-Fired Action with Removable Fire Control Unit – Why it matters: The entire trigger group drops out as one serialized unit, letting you swap grip sizes, calibers, or frame colors without buying a new gun.
- 1913 Picatinny Accessory Rail – Why it matters: You can mount a WML like a SureFire X300 or Streamlight TLR-1 for home defense, keeping both hands on the grip while illuminating your target.
- Two 9-Round Magazines – Why it matters: Nine rounds of .45 ACP is a solid capacity for a compact, and having a spare mag means you’re not caught flat-footed at the range or in a defensive scenario.
Who It's For
The P320 Compact in .45 ACP fits shooters who want a .45 that doesn’t feel like a boat anchor. It works for open carry, home defense, and even concealed carry if you dress around it. If you already own a P320 in 9mm, this gives you caliber interchangeability on the same FCU without retraining your grip or holster setup.
Pros & Cons
- Pro: SIGLITE night sights are standard, saving you $80–100 on aftermarket installs.
- Pro: Nitron finish resists holster wear and corrosion better than many blued or cerakote options.
- Pro: Modular FCU means you can swap to a full-size grip for range day or a subcompact for deep concealment.
- Con: At 28.3 ounces unloaded, it’s heavier than a typical polymer 9mm compact, so all-day IWB carry requires a sturdy belt and holster.
Comparison: Sig P320 Compact .45 vs. Zev Technologies OZ9 vs. Agency Arms AOM
| Feature | Sig P320 Compact .45 | Zev OZ9 | Agency AOM |
|---|---|---|---|
| Caliber | .45 ACP | 9mm only | 9mm only |
| Barrel Length | 3.9" | 4.2" | 4.0" |
| Capacity | 9+1 | 17+1 | 15+1 |
| Trigger | Striker-fired, factory 6-7 lb | Striker-fired, Zev adjustable | Striker-fired, Agency flat |
| MSRP | $649.99 | ~$1,400 | ~$1,600 |
| Night Sights | Included (SIGLITE) | Not included | Not included |
The Zev OZ9 and Agency AOM are race-ready 9mm platforms with premium triggers and slide cuts, but they cost more than double the Sig and don’t offer .45 ACP. The P320 Compact .45 gives you big-bore power at a price that leaves room for ammo and a holster.
Is the Sig P320 Compact .45 ACP suitable for concealed carry?
Yes, but it’s on the larger end of compact. With a 3.9-inch barrel and 28.3-ounce weight, it works best in a quality OWB holster under a jacket or an IWB holster with a sturdy belt. The grip length is similar to a Glock 19, so it prints more than a single-stack 9mm, but the .45 power is worth the trade-off for many carriers.
Can I use P320 9mm magazines in this .45 ACP model?
No. The .45 ACP P320 uses specific magazines that are wider and have a different feed geometry. 9mm and .40 S&W P320 mags will not lock into the .45 grip module. Stick with the included 9-rounders or buy factory Sig .45 mags.
Does the P320 Compact .45 come with an optics-ready slide?
No, the standard Nitron model does not have an optic cut. If you want a red dot, you’ll need to send the slide to a machine shop or buy the aftermarket Romeo1Pro slide assembly. The SIGLITE iron sights are still great for low-light use without a dot.
What holsters fit the P320 Compact .45?
Any holster molded for a P320 Compact with a 3.9-inch barrel and standard rail will work. Brands like Vedder, Tier 1 Concealed, and Safariland make specific options. Avoid holsters for the P320 full-size or subcompact, as the barrel length and trigger guard shape differ.
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✅ 30-day returns on unfired, undamaged firearms
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