How many cases of rifles did pike bishop and his gang steal from the us army train in wild bunch?

The Wild Bunch did not steal rifles from a U.S. Army train. The movie "The Wild Bunch" features a climactic scene where the gang attacks a train carrying weapons for the Mexican government, but the weapons are never identified as rifles.

The gang is primarily shown to be after the gold being transported on the train, and they do not specifically target any particular type of firearm.