The Ukrainian army’s newest howitzers also are among its oldest. On Sunday, the first video appeared online depicting ex-Lithuanian M101 howitzers in front-line use by Ukrainian forces, apparently somewhere in eastern Ukraine. The 105-millimeter M101 was the standard light howitzer for U.S. and allied forces ... in World War II. But the design’s age belies its effectiveness. The 2.5-ton M101 is a classic—an artillery piece that nearly perfectly balances weight, range and accuracy. The M101 was a battle-winner 80 years ago. In the hands of experienced, motivated gunners, it still can win battles today. Especially as those gunners combine the...