I lucked out.Also the average of 20 shots * 2/3 hit *5/6 wound *1/3 failed saves is only 3.7 so you have to get pretty lucky to put it down in one round as it has 6 wounds. If it has the suncannon (a fairer points comparison), you will lose most of the sternguard in return fire and/or get kicked to death in assault (only 1 wound on average even with the full squad firing on overwatch, subtantially less if the eldar shoot you a bit first)