Tank pan magazine
Here's a sketch of a simple tank autoloader concept. I don't think anyone tried this historically.
The ammo is stored in a non-rotating pan around the turret ring. There are blowout panels to direct explosions upward, so a hit will only cause the loss of a few rounds.
The turret has a small port to take in a round. A claw mounted along the barrel pulls the round in. A loading ramp bridges the gap (the gap allows for recoil and ejection).
Assuming a traditional crew layout, there's a gap in the magazine for the driver.
