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The Rock Island ACT-MAG is a straightforward aftermarket magazine designed to keep your P320 or M17 supplied with extra firepower at the range. With 17 rounds of 9mm capacity, it matches the standard load-out of your full-size Sig and gives you the flexibility to swap mags during extended shooting sessions.
This mag is built around blued steel construction paired with a corrosion-resistant finish, so it'll hold up to range use and regular handling. The polymer baseplate and follower team up with a quality steel spring to keep rounds feeding smoothly, while factory-cut witness holes let you do a quick visual round count without breaking the mag down.
The flush-fit design means it won't protrude below the grip on your full-size pistol, and the engineering meets strict tolerances to ensure reliable insertion and removal. Whether you're stocking up spare mags for training, setting up multiple loaded mags for competition, or just keeping backups for your duty or defensive setup, this ACT-MAG option delivers solid performance without the premium price tag of factory Sig magazines.
This ACT-MAG is designed for full-size P320 and M17 pistols and will fit flush with those models. It's also compatible with the P250 full-size platform. Keep in mind that it may not seat properly or fit flush in Carry, Compact, or Subcompact P320 variants due to their smaller grip frames.
The Rock Island ACT-MAG delivers the same 17-round capacity and reliable function as factory Sig magazines at a significantly lower cost. While both use steel construction and proven designs, the Rock Island option is a solid value-oriented choice for range training and backup mags. Some shooters prefer factory mags for critical duty use, but this aftermarket option performs well for most applications.
The factory-cut and numbered witness holes on the side of the mag let you count your rounds at a glance without unloading the magazine. This is handy at the range when you want to track how many rounds you've loaded or if you need to verify capacity quickly during practice.
Yes, the polymer baseplate is removable, which makes it easy to field-strip the magazine if you need to replace the spring or clean out any debris. The baseplate also includes a shock-resistant design to help protect components during quick mag changes.
The magazine is engineered for full-size P320 and M17 pistols. While it may function in Carry or Compact models, it will not sit flush with the grip frame and will protrude noticeably below the magwell. For those smaller frames, Sig offers purpose-built 10 and 15-round magazines that provide a proper fit.
Keep the magazine clean and dry, and occasionally inspect the spring and follower for debris. The blued finish will develop a patina over time with range use, but the corrosion-resistant treatment provides solid protection. If you store loaded mags long-term, rotate them occasionally to prevent spring set.
| UPC | 812285025476 |
|---|---|
| Manufacturer | |
| Manufacturer Part Number | 3209 |
| Brand Fit | Sig Sauer |
| Caliber/Gauge | 9mm |
| Capacity | 17rd |
| Model | |
| Model Fit | P320 |
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