The Karl Mortars had a caliber of 60cm and 54cm.
The huge German railway gun- Dora or Gustav- had a caliber of 80cm.
The "Little David" cannon- orignally designed by the US army to test aircraft bombs- had a caliber of
914mm.
However, Little David was never used in action. But since the question said "american artillery piece", the Little David would win.
The most appropriate "Biggest Gun" answer is the Dora/Gustav- mainly because it was the biggest gun ever
used in action.
The Karl Mortars were easily the biggest
self-propelled guns ever used.
Why do I get the idea that this "quiz" will not be graded?
