Just got some factory Sig P320 9mm mags today. They have a high visibility orange follower and witness holes on the back of the mag from 2 to 17. They say Made in Italy with the MecGar stamp.

Compared them to my older P320 mags that have black followers. The old mags have witness holes on the side at 5, 10, and 17 rounds.

Also, the top feed ramp on the new mags is approximately 1mm to 2 mm longer than the old mags.

This area in green is longer than the old mags.

Yup.

The new thirty rounders are the same way, but the witness holes are a bit more spread out.

The 17-round magazines have been available for about three years now. I think they were first shipped with some Legion models. The 15-round version appeared about two years ago, and the 21-round mags showed up in the last year.

What has made them a surprise to many people is that SIG seems to be continuing to produce and sell the older version alongside these, and most dealers don’t seem to carry the orange follower mags. They sometimes show up at Cabela’s displayed alongside the regular mags. The most reliable source I’ve found is Army / Air Force post exchange stores. There are only a handful of online dealers that sell them, if you search for P320 magazines with high visibility orange followers.