Know Your Weapons: The .30-40 U.S. Krag-Jorgenson in Combat Posted on 23 April 2022 by The Tactical Hermit THE .30-40 U.S. KRAG-JORGENSEN IN COMBAT I had a couple of Krag’s I traded for over the years but I never really cared for them. They were too long and the action was not near as smooth as a Mauser. Caliber wise they are like shooting a .30-06.