Beretta is the oldest and considered the largest barrel maker in the world. No one dedicates more time to selecting barrel steel. The new Beretta DT11 barrels boast:
Steelium technology is a unique manufacturing process that transforms the special tri-alloy steel into an exceptional barrel. Through techniques like deep drilling, cold-hammer forging and special vacuum distension, Steelium creates the ideal characteristics for the best ballistic performance available today.
... to Steelium Pro
Stemming from Beretta’s exclusive manufacturing process and thanks to our cold-hammer forging technique, Steelium Pro marries the benefits of Steelium technology to give way to a new barrel internal profile. The result is the creation of a progressive conicity that removes any sudden constriction, allowing the DT11 to fix new performance standards.
The graphic below shows the difference between traditional constriction and the progressive constriction in the Steelium Pro barrels of the DT11: the removal of any sudden steps prevents the pellets from crushing against the constriction walls, resulting in improved patterns with less felt recoil and consistent, unaffected muzzle velocity.