2016 1 Kilo Proof Kookaburra Diameter of 100.6 mm (just under 4 inches) and a thickness of 14.6 mm (0.575 inches) 32.15 oz
If you add medals to the mix, this piece is far larger than any of my coins. This medal, which shown beside a Morgan Dollar, was awarded to General Zachary Taylor for his leadership during the Mexican War. This medal is bonze. The piece that the government awarded to Taylor was solid gold.
I am a nickel guy so the 38mm Lafayette Dollar seems enormous to me. And I know we said no medals, but the Lafayette Dollar design came from the 1881 Surrender at Yorktown medal measuring 50.8mm.