My Knex M19A4 Pistol By smithinator in LivingLEGO & K'NEX972120Save PDFFavoriteIntroduction: My Knex M19A4 PistolBy smithinatorFollow More by the author: About: my top 5. 5.ajleece 4.Knex builder freak 3.The Jamalam 2.Barrax 1.YOU! More About smithinator »This is my 5th instructable so I hope you like it (it can fire up to approx 39 feet).