Indexable milling insert having side supporting valley, and a milling tool

A milling tool comprising:

• a milling cutter body;
• and
• at least one milling insert mounted in a pocket of the cutter body, the at least one milling insert including a first end surface, a second end surface, a side surface extending between the first end surface and the second end surface, and at least one cutting edge defined by an intersection of at least one of the first end surface and the second end surface with the side surface, wherein the at least one cutting edge includes a radiused component—having a first end and a second end and first and second components at the first and the second ends of the radiused component respectively, the first and second components being less curved than the radiused component, the side surface including at least one substantially V-shaped valley formed by first and second support surfaces, wherein male or female insert mounting structures of the milling insert mate with corresponding female or male milling cutter body mounting structures on a bottom surface of the pocket.