Accuracy of the Sturmtiger:
(ripped from the following excellent page):
It was found that the rocket mortar was rather inaccurate out to its maximum range. This should not be surprising if one recalls the German small arms industry's experiments with rocket cartridges. As the propellant is used up, the center of gravity will shift, causing the projectile to lose its accuracy very rapidly. Since the 38cm RTgs projectile works on the same principle, then, you can see why its accuracy would suffer at range. However, given the mission of the Sturmtiger, firing at the weapons full range would probably not be the order of the day, given that, in the Sturmtiger's ideal combat environ, it'd be the urban combat arena, where ranges are dramatically short. However, given the war situation as it was by the time the Sturmtiger entered the battlefield, they often found themselves as defensive weapons with little opportunity to engage in battle on their own terms.