The U.S. Army has ordered another 95 Stryker wheeled armored vehicles, including 14 equipped with a 105mm gun (Stryker MGS) and 17 chemical/biological/nuclear warfare detection vehicles (Stryker NBCRV). The MGS has had a lot of technical problems, and only 14 are being ordered so that they can be used to work out the kinks. Other nations have built vehicles like the MGS successfully, and the army will order another 58 MGS versions once the current design has become more reliable. Part of the problem is that the army decided to not to use the existing M-8 AGS (armored gun system), but to build a new 105mm self-propelled gun system using a Stryker chassis. The M-8 was developed and tested in the 1990s, for airborne troops, but did not go into mass production. Infantry like the idea of having a 105mm gun vehicle available to fire directly at enemy troops in buildings or fortifications. The M-1 tank has made itself very useful in urban warfare by using its 120mm gun to blow away opposition that the infantry cannot easily deal with using lighter weapons. But the MGS is a new piece of equipment, and there are reliability problems with the autoloader and turret. Eventually, the army plans to build 2,100 Strykers, enough to equip six brigades. Currently, only two brigades have been formed.