Revolutionary War Spontoon

S7, E10: Four smiths spring into action when they are tasked with creating signature blades from different sized springs. The smiths battle through two tough rounds, fighting through canisters and failing forge welds for an opportunity to leap forward in the competition. After a brutal testing bout, the two remaining smiths head home to recreate one of the most distinguishing weapons of the Revolutionary War: the Sergeant's Spontoon. Which smith will survive the battery of tests to earn the title of Forged in Fire champion and $10,000?