Fire-breather or bayonet-biter?

An “Eisenfresser” (“iron-muncher”) is a blowhard or braggart, especially when it comes to (claimed) military exploits.

In The Magic Mountain, Dr Behrens contrasts Hans Castorp’s talent for being sick with his cousin Joachim’s unquenchable urge to rejoin his regiment, jeopardising his long-term health (hmm…):

“[Eisenfresser] like him don’t need much in the way of brains, but you, a more sensible civilian, a man with a bourgeois education, must set his head straight before he does something stupid.”

Joachim doesn’t boast or brag, though - he’s just desperate to get well and fight.

I liked “Gung-Ho Jo”, but the phrase dates from the mid-20th century. Too late.
Next try was “Balaclava Bill” in reference to the absurd valour of the Charge of the Light Brigade during the Crimean War. Right period, but the allusion’s probably too obscure.

So now I’m hesitating between a more generic “fire-breather” and something like “bayonet-biter”; the latter sticks more closely to the original and conjures up the horrors that awaited enthusiastic volunteers in the trenches.

Another suggestion I've received is "lead-eater" from "eat lead" (h/t Roland Glasser 👏 ) . . . but is "fressen" the lesser part of valour? (sorry)

Choices, choices…