Individidual clubs vary as to round count and number of stages obviously based on number of available bays and time. Then there is the Sanctioned Matches which require 8 stages, and a minimum of 100 shots.

The amount of rounds you can carry per stage is dependent on your weapon.

Revolver, 6 rounds in the weapon, plus 3 reloads - 24
Pistol up to 10 rounds per magazine, 3 magazines total (1 in the pistol, 2 spares, 1 round in the chamber) - 31

If you carry a compact pistol or basic 1911, 3x8 round magazines, 1 in the chamber - 25. Regardless of the pistol, you are only allowed 3 magazines per stage.

The courses are designed to have a maximum targets/ minimum number of shots. READ - The maximum number of targets allowed per stage at 9 requiring 2 "Down 0" hits to eliminate = 18 shots.

The local club that I RSO for only has 4 bays, so there is generally only 4 stages, with the occasional 5th stage with 2-4 strings (each string for the stage is in a different bay) and each of those strings will only have maybe 6 shots minimum (3 targets). So we tend to max out the number of targets. Realistic encounters, not so much, but you did come out to shoot, not fire a handful of rounds then sit and wait for an hour before you shoot again.