If you read the codex on the rupture cannon you wonder why it isn't blast....
leman russ demolisher... 165points... 24" S10 AP2 Large blast. so it scatters, and it can't be hurt by anything S3 and below, whereas T6 tyrannofex can be killed by a lasgun... :(
2 shots 6" range, Strength 6 and rending. min penetration is 7 max penetration is 15. so a small chance of taking out a 200+ point tank the turn it comes on. Otherwise its useless :p
I think the message in this advert is wear those trainers you can jump over a fence, have a massive belly you can crash through the fence.....