GSSF shoots are once a year ordeal. Are you talking USPSA, IPSC, or IDPA matches? I shot a GSSF match at my local range in June. I used a 9mm for that-G17. One reason for using a caliber of 40S&W or larger is to get into the 'major' category in some of the other sport shooting venues. 9mm is minor. Get whatever you can shoot best and fastest for competition.