The phrase “Missouri War Axe” really has two different meanings. From my understanding, it was contemporary collectors who termed the “MWA” phrase, referring to what are generally 19th century large flared axe shaped tomahawks, sometimes without shaped cutouts. However, the term was derived, at least in part, from the Lewis and Clark journal descriptions of the “war axes” or “battle axes” they observed in the possession of the western Indians during their famous journey. They ended up setting up a blacksmithing business to cater to this “war axe” trade, both manufacturing new ones, as well as repairing existing examples.
“Spontoon” style pipe tomahawks are perhaps the earliest style of pipe tomahawk, which itself is a truly North American invention arising from the clash of cultures and power converging in 18th century colonial America. Early europeans arriving in the new world commonly carried pole-arms with them, which were relics-themselves from European battlefields and the old manners of waging war.