
Availability: In Stock
The Strike Industries Aluminum Extended Magazine Plate for the SIG SAUER P320 in 9mm is a precision-machined basepad engineered to add capacity and control to your duty, competition, or carry setup. Machined from 6061-T6 aluminum and weighing just 1.97 oz, this extended mag plate fits OEM SIG SAUER P320 magazines in 21, 17, and 15-round capacities, with the included extended spring allowing the 21-round body to achieve a plus-5 round advantage over factory basepads. Installation is straightforward—no gunsmithing required—and the slim, snag-free profile won't catch on gear or clothing while delivering the clean lines shooters expect from Strike Industries.
Built for competitive shooters, this extended magazine plate complies with USPSA 140mm race division limits, making it a legal choice for sanctioned matches. The anodized SI BLACKLINE finish resists corrosion and looks sharp on the line or in the field. Whether you're running a P320 in a duty holster, a competition rig, or a carry setup, this basepad gives you extra rounds without sacrificing the ergonomics or concealability the platform is known for.
Installation is intuitive: the included hex tool and two M4x3mm set screws hold everything in place. Strike recommends not exceeding 7 in-lbs of torque on the set screws to avoid damage. Note that due to manufacturing variance in stamped steel magazines, initial capacity may be +4 rounds; the included spring will break in to achieve the full +5 capacity over time. The extended spring is optimized for the 21-round magazine body; use OEM SIG springs with 17 and 15-round magazines.
| Brand | Strike Industries |
| Fits | SIG SAUER P320 (9mm) |
| Compatible Magazine Capacities | 21-round, 17-round, 15-round OEM SIG SAUER bodies |
| Added Capacity | Up to +5 rounds (9mm) |
| Material | 6061-T6 Aluminum |
| Weight | 1.97 oz |
| Finish | Anodized SI BLACKLINE |
| USPSA Compliant | Yes (140mm race division) |
| Set Screw Torque Limit | 7 in-lbs (0.79 Nm) |
| What's Included | Extended magazine plate, extended spring (21-rd), 2x M4x3mm set screws, 2mm hex tool, warning card |
No. This plate is designed for OEM SIG SAUER P320 magazines. It is not compatible with aftermarket brands such as ACT, ProMag, or ETS magazines, and may not fit certain aftermarket magwells.
The extended spring included with this plate is optimized for the 21-round magazine body and is required to achieve the full +5 capacity with that magazine. For 17 and 15-round magazines, use the OEM SIG SAUER spring; these will function reliably with the extended basepad but won't gain the extra +5 rounds.
Yes. The Strike Industries extended magazine plate complies with USPSA 140mm race division limits, making it a legal choice for sanctioned matches and competitions.
With the 21-round magazine body, the included extended spring may initially deliver +4 rounds due to normal manufacturing variation in stamped steel magazines. The spring will break in over time and achieve the full +5 capacity with use.
SKU: 144599708 • Width: 4in • Height: 1.25in • Depth: 10.75in • Weight: 0.13oz






Availability: In Stock
The Strike Industries Aluminum Extended Magazine Plate for the SIG SAUER P320 in 9mm is a precision-machined basepad engineered to add capacity and control to your duty, competition, or carry setup. Machined from 6061-T6 aluminum and weighing just 1.97 oz, this extended mag plate fits OEM SIG SAUER P320 magazines in 21, 17, and 15-round capacities, with the included extended spring allowing the 21-round body to achieve a plus-5 round advantage over factory basepads. Installation is straightforward—no gunsmithing required—and the slim, snag-free profile won't catch on gear or clothing while delivering the clean lines shooters expect from Strike Industries.
Built for competitive shooters, this extended magazine plate complies with USPSA 140mm race division limits, making it a legal choice for sanctioned matches. The anodized SI BLACKLINE finish resists corrosion and looks sharp on the line or in the field. Whether you're running a P320 in a duty holster, a competition rig, or a carry setup, this basepad gives you extra rounds without sacrificing the ergonomics or concealability the platform is known for.
Installation is intuitive: the included hex tool and two M4x3mm set screws hold everything in place. Strike recommends not exceeding 7 in-lbs of torque on the set screws to avoid damage. Note that due to manufacturing variance in stamped steel magazines, initial capacity may be +4 rounds; the included spring will break in to achieve the full +5 capacity over time. The extended spring is optimized for the 21-round magazine body; use OEM SIG springs with 17 and 15-round magazines.
| Brand | Strike Industries |
| Fits | SIG SAUER P320 (9mm) |
| Compatible Magazine Capacities | 21-round, 17-round, 15-round OEM SIG SAUER bodies |
| Added Capacity | Up to +5 rounds (9mm) |
| Material | 6061-T6 Aluminum |
| Weight | 1.97 oz |
| Finish | Anodized SI BLACKLINE |
| USPSA Compliant | Yes (140mm race division) |
| Set Screw Torque Limit | 7 in-lbs (0.79 Nm) |
| What's Included | Extended magazine plate, extended spring (21-rd), 2x M4x3mm set screws, 2mm hex tool, warning card |
No. This plate is designed for OEM SIG SAUER P320 magazines. It is not compatible with aftermarket brands such as ACT, ProMag, or ETS magazines, and may not fit certain aftermarket magwells.
The extended spring included with this plate is optimized for the 21-round magazine body and is required to achieve the full +5 capacity with that magazine. For 17 and 15-round magazines, use the OEM SIG SAUER spring; these will function reliably with the extended basepad but won't gain the extra +5 rounds.
Yes. The Strike Industries extended magazine plate complies with USPSA 140mm race division limits, making it a legal choice for sanctioned matches and competitions.
With the 21-round magazine body, the included extended spring may initially deliver +4 rounds due to normal manufacturing variation in stamped steel magazines. The spring will break in over time and achieve the full +5 capacity with use.
SKU: 144599708 • Width: 4in • Height: 1.25in • Depth: 10.75in • Weight: 0.13oz
