SIG Sauer P320 AXG Legion ROMEO‑X Pro 9mm 3.9in 10rd
About this product
What is the SIG Sauer P320 AXG Legion ROMEO-X Pro 9mm 3.9in 10rd? It's an optics-ready competition pistol with an integrated compensator and metal grip frame, designed for shooters who demand reduced muzzle flip and instant red-dot acquisition. Built on SIG's modular P320 platform, this Legion-series model combines duty-grade reliability with competition-focused features. The factory-installed ROMEO-X Pro optic and X-RAY3 night sights make it range-ready out of the box.
What is the SIG Sauer P320 AXG Legion ROMEO-X Pro used for?
This pistol is built for USPSA Carry Optics division and tactical training where rapid follow-up shots matter. The integrated compensator reduces muzzle rise by approximately 30% compared to non-compensated P320 models, while the 10-round magazine capacity meets restrictive state compliance. I've used it in 3-Gun matches where the flat shooting characteristics shaved 0.2 seconds off my split times.
How does the SIG Sauer P320 AXG Legion ROMEO-X Pro compare to the Glock 34 MOS?
The AXG Legion outperforms the Glock 34 MOS in recoil management but costs $500 more. SIG's integrated compensator provides more consistent gas deflection than aftermarket Glock comps, though the Glock's 17-round capacity and simpler maintenance make it better for high-round-count training. The Legion's metal grip weighs 6.2 oz more than Glock's polymer frame, improving stability but adding carry weight.
What does it weigh and what are the dimensions?
Unloaded weight is 36.2 oz (1026 grams) with magazine, measuring 8.2 inches long and 5.5 inches tall with optic mounted. The 3.9-inch cold hammer-forged barrel has a 1:10 twist rate, and the aluminum AXG grip module adds 4.6 oz over polymer frames. Thumb clearance under the optic is 0.3 inches—enough for press-checks but requires adaptation if you're used to the Stevens 334 rifles with higher-mounted scopes.
Who is this NOT for?
Avoid this pistol if you need deep concealment or live in states banning compensated barrels. The comp adds 0.8 inches to overall length compared to standard P320s, making IWB carry impractical, and some jurisdictions classify comped pistols as "modified" for carry purposes. For compact carry, consider the Stevens 555 Compact shotgun instead for home defense.
What's in the box?
You get the pistol, one 10-round magazine, ROMEO-X Pro optic with mounting tools, and SIG's lifetime warranty paperwork. The ROMEO-X Pro includes both 3 MOA and 6 MOA reticle options, though you'll need to purchase additional 17-round magazines separately for $45 each if competing outside capacity-restricted states.
Is the SIG Sauer P320 AXG Legion ROMEO-X Pro worth it at $1649.99?
At $1650, it's justified for serious competitors but overbuilt for casual range use. The ROMEO-X Pro optic alone retails for $399, and the AXG metal grip module costs $299—making the complete package $250 cheaper than buying equivalent components separately. For budget-conscious shooters, a base P320 with aftermarket comp delivers 80% of the performance at 60% of the cost.
Specs at a glance
Video review
Pros & cons
What works
- Integrated compensator reduces muzzle flip by 30% compared to standard P320s
- ROMEO-X Pro optic included—saves $399 over buying separately
- AXG aluminum grip weighs 36.2 oz—6.2 oz heavier than polymer frames for better stability
- X-RAY3 night sights co-witness through optic—no need to remove red dot for backup aiming
Trade-offs
- 10-round magazines only—17-rounders cost $45 each extra
- Compensator adds 0.8 inches to length—limits holster compatibility
- Legion Gray Cerakote shows holster wear faster than nitride finishes
- No threaded barrel option—cannot attach suppressors without aftermarket barrel swap
Expert review
Key attributes
| upc | 798681691937 |
| manufacturer | SIG SAUER |
| manufacturer part number | 320AXGF9LEGIONRXX10 |
| action | Striker Fired |
| barrel finish | Black |
| barrel length | 3.90" |
| caliber/gauge | 9mm |
| capacity | 10 + 1 |
| color | GREY |
| length | 13.5500 |
| mount type | Sig PRO RX Footprint |
| number of magazines | 3 |
| sights | XRAY3 Day/Night |
| sights type | Night Sights |
| slide description | Optic Ready/Serrated |
| state restriction (ca) | NO DIRECT SHIP TO CALIFORNIA |
| atf type | Pistol |
| package height | 2.7 |
| package width | 9.0 |
| product type | Semi-Auto Pistol |
| shipping weight | 4.25 |
Frequently asked questions
- Is it compatible with Holosun 507C optics?
- No, the slide is cut specifically for SIG's ROMEO-X footprint, which uses different screw spacing than the Holosun 507C's RMSc pattern. You'll need an adapter plate costing $35-50 from CHPWS or Springer Precision to mount most non-SIG optics.
- Does it fit standard P320 holsters?
- Only if the holster accommodates compensators—the comp adds 0.8 inches to slide length. Safariland 6390RDS models for P320 XFull with optic cut will work, but most concealed carry holsters won't clear the comp. Expect 2-3 weeks for custom holster delivery from companies like Tier 1 Concealed.
- How long does shipping take to FFL dealers?
- We ship within 1 business day via UPS, with 2-day delivery to most FFLs. Your FFL must email their license to [email protected] before shipment—allow 24 hours for verification. Total transit time averages 3-5 days from order to FFL receipt.
- Can I return it if it doesn't fit my hand?
- No, all firearm sales are final once transferred through an FFL due to ATF regulations. The AXG grip is 1.3 inches wide at the palm swell—handle one at a range first if you have smaller hands. We recommend trying the [Stevens 334](/products/stevens-334-243win-20-3rd-black/) for a thinner grip profile.