loaded gun plus 3 mags at the start signal
From IDPA rule book
8.1.3 Division Capacity
8.1.3.1 SSP – 10 rounds
8.1.3.2 ESP – 10 rounds
8.1.3.3 CDP – 8 rounds
8.1.3.4 CCP – 8 rounds
8.1.3.5 REV – 6 rounds
8.1.3.6 BUG – 6 rounds total
8.1.3.7 In SSP, ESP, CCP, and CDP, and semi-auto BUG the shooter will also start with one round in the chamber, unless the CoF description requires otherwise.
8.1.4 Loading Device (Magazine, Speed Loader, Moon Clip) Count
8.1.4.1 Shooters starting with 8 or more rounds in all loading devices are allowed to start with the loaded firearm plus two additional loading devices.
8.1.4.2 Shooters starting with 6 or 7 rounds in all loading devices are allowed to start with the loaded firearm plus three additional loading devices.
8.1.4.3 Shooters starting with 5 or fewer rounds in all loading devices are allowed to start with the loaded firearm plus four additional loading devices.
8.1.4.4 No additional loading devices beyond the above limits may be used during a string.