While the SA-35 comes with 15-round magazine (Mec-Gar) these have been available for quite awhile, and 13 rd mags are perfectly useable. This S.A. Camp article describes the differences between the two.
Mec-Gar 9mm Hi Power Magazines: 13 vs. 15-Round
On the left is a Mec-Gar 13-round Hi Power magazine and on the right, a 15-shot one. They are the same length.
Mec-Gar 9mm Hi Power Magazines: 13 vs. 15-Round
![image004.jpg](/forum/proxy.php?image=https%3A%2F%2Fhipowersandhandguns.com%2Fmec-gar%25209mm%2520Hi%2520Power%2520magazines%252013%2520vs%252015%2520shot_files%2Fimage004.jpg&hash=d8bcbde0a5121acbb25fb004e61423a3)
On the left is a Mec-Gar 13-round Hi Power magazine and on the right, a 15-shot one. They are the same length.