Most modern Western tanks store ammo in a separate compartment with blowout panels and automatic loading doors to the main turret compartment. This is meant to shield the crew from the effects of ammo cookoffs. This compartment is in the tanks turret bustle in the rear.
Ex Soviet tanks store ammo in the hull or in the autoloader magazine around the inside of the turret basket. This often causes the catastrophic destruction of the tank (the now infamous “turret toss”) with the instant loss of the crew.
Challenger stores ammunition in the turret