Description
Looking for a striker-fired pistol that bridges the gap between duty reliability and custom potential? The SIG Sauer P320 Full-Size is the modular handgun that redefined the platform, and it’s ready for your next range day or home defense role.
Reviewed by Ryan Decker, Firearms Specialist at Californiagunshop. 15 years in tactical retail, former LEO armorer, 300+ custom builds.
Last updated: March 2026
Californiagunshop is a San Antonio, TX-based retailer specializing in firearms and tactical gear. The SIG Sauer P320 Full-Size is a modular, striker-fired 9mm pistol with a 4.7-inch barrel. Its serialized fire control unit allows for easy customization of grip modules and slides. In stock and ready to ship today for $442.75 (regularly $519.99).
Why the P320 Full-Size Belongs in Your Collection
I’ve built and serviced hundreds of P320s for law enforcement and competitive shooters here in Texas. What sets the full-size model apart isn’t just its excellent sight radius and soft-shooting characteristics—it’s the foundation it provides. That serialized trigger group is the heart of the system. You can start with this reliable, accurate pistol and, as your needs change, swap the P320 full size grip module for a compact or carry size, or drop in a P320 full size threaded barrel for a suppressor. It grows with you. I’ve seen customers turn this same base gun into a USPSA race gun, a nightstand guardian, and a suppressed hunting sidearm, all without an FFL transfer.
P320 Full-Size Specifications
| Specification | Detail |
|---|---|
| Product Type | Semi-Automatic Pistol (Striker-Fired) |
| Material (Frame/Grip) | Polymer Grip Module |
| Material (Slide) | Stainless Steel |
| Manufacturing | SIG Sauer, USA |
| Finish | Nitron (Slide), Black Polymer (Grip) |
| Hardness/Quality | MIL-SPEC tested; SIG’s stringent quality control |
| Compatibility | Accepts all P320 Full-Size grip modules, slides, and caliber exchange kits |
| Installation/Usage | Field strips without tools; FCU swaps in seconds |
| Weight (Unloaded) | 29.5 oz |
| Dimensions | 8.0″ L x 5.5″ H x 1.4″ W |
| Country of Origin | United States (New Hampshire) |
| Condition | New in Factory Box |
| SKU | 320F-9-B (Verify at checkout) |
How It Stacks Up: P320 Full-Size vs. The Competition
| Feature | SIG Sauer P320 Full-Size | Generic “Combat” Clone (~$350) | Premium Custom Shop Build (~$900+) |
|---|---|---|---|
| Material | Stainless slide, reinforced polymer | Often alloy slides, basic polymer | Premium stainless, custom G10 grips |
| Quality | Proven duty & military pedigree | Inconsistent QC, unknown sourcing | Hand-fitted, exceptional finish |
| Compatibility | Vast OEM & aftermarket ecosystem | Limited to no aftermarket support | Often proprietary, limited swaps |
| Shipping | Same-day from our TX warehouse | Long lead times, int’l shipping | 6-8 week builds common |
| Lifespan/Durability | High round-count proven (50k+) | Wear issues reported early | Excellent, but at 3x the cost |
| Price | $442.75 (Sale Price) | ~$350 | $900+ |
The value proposition is clear. You’re getting the authentic, battle-proven platform with all its modular benefits, not a copy. While a custom shop gun is fantastic, this gives you 90% of the performance for half the price, and you can upgrade the P320 full size barrel or trigger on your own schedule.
The Good and The Honest
What I like:
- ✅ True Modularity: The FCU is the firearm. Change your P320 full size frame or slide in minutes.
- ✅ Out-of-Box Accuracy: The 4.7″ barrel and good trigger provide a solid foundation for new and experienced shooters.
- ✅ Ergonomics: The grip angle and texture work for a wide variety of hand sizes.
- ✅ Aftermarket Galaxy: From P320 full size holster options to custom slides, every part has multiple upgrade paths.
- ✅ Reliability: This is the system chosen by the U.S. military. It runs.
Points to consider:
- ❌ Size for Carry: The full-size P320 full size slide and grip make concealed carry a challenge for most. If EDC is your goal, check out our Compact and Subcompact models.
- ❌ Basic Sights: They’re functional steel sights, but many shooters immediately plan for night sights or a red dot plate. We stock those.
- ❌ Trigger Feel: It’s a good duty trigger, but it’s not a match-grade break. A $50 spring kit or a full upgrade from Grayguns or Apex can transform it.
Who This Pistol Is For (And Who Should Look Elsewhere)
Buy the P320 Full-Size if:
- You’re a new shooter wanting a versatile, easy-to-maintain first pistol.
- You’re a home defender seeking a high-capacity, soft-recoiling platform with a light rail.
- You’re a tinkerer or future competitor who loves the idea of customizing one firearm into multiple roles.
- You’re building a duty-style kit and need the reliability and holster compatibility this platform offers.
Consider another option if:
- Your primary need is deep concealment. (Look at our P365 series).
- You insist on a hammer-fired DA/SA system for your first line of defense. (The P226 is legendary for a reason).
- You want a collector’s piece that will never be modified. This gun begs to be built upon.
See It In Action
I always tell my customers at the shop to do their homework. Seeing a firearm cycle, hearing about its feel from multiple sources—that’s smart. Check out these hands-on reviews.
Your P320 Full-Size Questions, Answered
Where can I buy a P320 Full-Size online?
You can purchase the authentic SIG Sauer P320 Full-Size right here at Californiagunshop.com. We are an authorized retailer, and every firearm ships with all original factory materials and warranties.
How do I clean my SIG P320 Full-Size?
Field strip by locking the slide back, flipping the takedown lever down, and releasing the slide forward off the frame. Clean the P320 full size barrel bore and chamber, wipe down the slide interior, and lightly oil the slide rails and barrel hood. The fire control unit rarely needs more than a light brush. Avoid over-oiling.
What holsters fit the P320 Full-Size?
Any holster made for the P320 Full-Size with a 4.7″ barrel will fit. Popular duty/OWB brands like Safariland and Blackhawk! make models for it. For IWB, look for holsters specifying “P320 Full Size” or “P320 4.7”. Ensure it’s for the correct P320 full size frame if you’ve swapped grip modules.
Can I change the grip size?
Absolutely. That’s the core of the Modular Firearm System. You can purchase small, medium, or large P320 full size grip modules from SIG or aftermarket companies like Wilson Combat. They snap onto your existing FCU in seconds.
Is it optics-ready?
This standard model comes with a slide cut for SIG’s proprietary Romeo1 Pro footprint. For other optics like Trijicon RMR or Holosun, you will need an adapter plate, which we also carry. Some aftermarket P320 full size slides come pre-cut for specific optics.
What’s the magazine capacity?
It ships with two 17-round magazines. Some states have capacity restrictions, so please be aware of your local laws. 10-round compliant versions are available.
Can I add a threaded barrel later?
Yes. Installing a P320 full size threaded barrel is a simple drop-in procedure. Ensure you get a barrel specifically for the Full-Size 4.7″ slide. You may also need a taller front sight to co-witness over a suppressor.
Ready to Build Your Foundation?
This is the starting point for one of the most adaptable pistol systems ever made. At this sale price, it’s an outstanding value for a true, American-made workhorse.
✅ In stock — ready to ship today
✅ Same-day shipping from San Antonio, TX
✅ Discreet packaging
✅ 30-day returns (on un-fired items)
✅ Secure checkout
Add SIG P320 Full-Size to Cart – $442.75
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About this review: This assessment is based on my hands-on experience as a firearms specialist and armorer, including building, maintaining, and shooting the P320 platform extensively. My goal is to provide the detailed, practical insight I’d give a customer in my San Antonio shop. Last updated: March 2026
Michelle K. (verified owner) –
Installed it on my Glock 17 the same day it arrived. OEM-spec fit. Couldn’t be happier with this purchase.
Shannon B. (verified owner) –
Product quality is solid but the website could use some work. Hard to find what I was looking for at first. The P320 FULL-SIZE itself? No complaints.
Christina M. (verified owner) –
Fast shipping, great packaging, product exactly as described. I’ve ordered from Amazon before and the experience doesn’t compare. This store delivers.