 There are some differences between the IPSC and USPSA Handgun Open divisions regarding major power factor requirements and maximum magazine length rules.While IPSC Open still require the major power factor of 160 kgr·ft/s which was proposed by USPSA at the 1999 General Assembly, USPSA changed the major power factor of USPSA Open division to 165 kgr·ft/s the following year in 2000.Thus, the threshold for making major power factor is 165 kgr·ft/s in all USPSA handgun divisions, while IPSC separates its power factor requirements into 160 kgr·ft/s for Open and 170 kgr·ft/s for all other all other handgun divisions.