The U.S. Army's program to build a new self-propelled artillery weapon (the Crusader) has run up against unfavorable technical and historical trends. The army has not gotten a new self-propelled gun since the M-109 was introduced in early 1960s. The M-109 was in turn based on all the battlefield experience gained from the first generation self-propelled guns during World War II. The main reason for replacing the (now much upgraded) M-109 was, well, there really wasn't any compelling reason for a new gun. In fact, the M-109 had lost a lot of work to the 1980s era MLRS. The rockets fired by the MLRS had a longer range, were more destructive and just as accurate as the M-109s 155mm cannon. But the artillery community has been agitating for a new gun for some time. The cannoneers had a large wish list and during the 1980s there was so much money sloshing around the Pentagon that the Crusader project was born. The wish list was long, containing nifty stuff like liquid propellant, heat tolerant barrels, lots of computers and an armored resupply vehicle. Typical peacetime excess, and many of the new tech features didn't work out and were dropped. Moreover, the Crusader was designed with the Cold War in mind. This led to a very heavy system. This ran afoul of the army's late 1990s program to get light and fly quickly to far off hot spots. So Crusader was redesigned to remove over ten tons of unwanted weight. But many officers, and a lot more civilian officials, want Crusader dead. Better to spend the money on more self-propelled mortars and variants on the MLRS (lighter versions, nifty new rocket designs.) But once defense projects get to a certain point (like where the Crusader now is), they become difficult to kill. Which is why we will enter our next war with the venerable M-109.