Editing MBT-70 (section)

===Problems===
An unanticipated problem was that the drivers complained of disorientation when the turret was rotated, contrary to the predictions of the designers who felt the location of the cupola near the center of rotation would eliminate this effect. The German 120mm gun proved excellent, although only firing APFSDS and HEAT, but the XM150 gun/launcher had serious problems. The similar but smaller XM81 gun/launcher mounted on the [[M551 Sheridan]] proved to be just as troublesome. There were also several problems with the ammunition. The caseless design made conventional tank rounds too vulnerable to water. Wet rounds expanded so they would not fit into the barrel anymore or left hard residues after being fired.<ref name="DerSpiegel" />

The auto-loader was capable of handling the Shillelagh missile without problems, but the combustible cases of the tank rounds could be deformed by it.<ref name="DerSpiegel" /> As is often a problem with caseless ammunition, the ammunition also had a tendency to "cook-off", or fire prematurely, due to heat build-up in the barrel from previously fired rounds. The attempted solution, to only carry a single round with the balance in missiles, also proved unacceptable. Deployment of the 20mm anti-aircraft cannon also proved difficult and the weapon itself was overcomplicated and nearly impossible to use effectively.{{citation needed|date=November 2010}}

Another problem of the MBT-70 was the increasing weight. While at the beginning of the project, a weight of some {{convert|46.3|t}} was projected, it increased to {{convert|54|t}} during development, which forced the designers to redesign some elements, so that finally a weight of {{convert|50.3|t}} was reached, still higher than required.<ref name="DerSpiegel" /> This meant that the MBT-70 would require its own armored recovery vehicles and bridge-launching systems.{{cn|date=June 2024}} Germany became concerned with the excessive weight of the tank. One solution proposed removing radiation hardening from the turret, but this called into question the wisdom of the driver-in-turret configuration, which was intended to protect the crew in the event of a [[Nuclear explosion|nuclear blast]].{{sfn|Hunnicutt|2015|p=142}} 

Commentators on the MBT-70 typically assert that though it was innovative in many respects, the project was ruined by the use of too many untried and unproven technologies. Senator [[J. William Fulbright|James W. Fulbright]] quipped that to drive an MBT-70, a [[master's degree]] from a technical institute would be required.<ref name="DerSpiegel" />