It depends on the caliber and the shooter's experience. I wouldn't shoot 100 round of factory .44 Magnum. 100 rounds of .22LR? No problem! But 100 rounds of .44 Mag? That's a good way to develop a serious flinch unless you've already got a lot of .44 Mag experience.
It depends on shooting experience you've already had. If this is your first time out, I'd keep the target at a range close enough that you can be sure of keeping all shots on it. Once you can keep all the shots on target and in a small group at that range, move the target further out. Repeat until you've used up the 100 rounds, but only if you haven't developed a flinch.