Assault as a can opener

I want to dispel a popular myth, the best way to kill a vehicle in 40k is shooting. Lets look at this you need to be able to see it and it needs to not have smoke up, you need to be able to roll to hit it, you'll likely be against its hardest armor facing. Then you have to get a penetrating roll. Typically your anti shooting is only 1 shot per unit, 2 if your lucky. Melta is an excellent choice for this operation, however look at the ranges you require to get the full benefit of the majority of melta weapons, you either have to 12"in for a multimelta or 6"in for a melta gun. That puts you into assault range, or rapid fire range of your opponent.

An a perfect world your shooting will blow up or disable the enemies armor, however anyone that plays regularly realizes that only in the nebulous world of numbers does that always hold true. In reality you will miss your shots, you will fail to penetrate, and someone will make 100% of their cover saves.

Assaulting a vehicle changes the game first and foremost you always hit a vehicle on rear armor. Which is typcially the weakest armor it has. The mighty Leman Russ and its many variants still only have a max rear armor of 11. Much better then the 14 front and 13 sides you'd normally have to deal with while shooting. Also many units are either equipped with or can purchase grenades. Meaning if you have Krak grenades you now have a str6 attack on rear armor on a standard marine or even a marine scout. You will hit depending on how far your opponent moved, sometimes you need 4's sometimes you need 6's but sometimes you autohit. But this also means you are throwing more dice at the problem then typically if you are shooting at the vehicle as not all soldiers carry antitank weapons usable in the shooting phase.

The dangers of assaulting the vehicle are if you explode the vehicle you expose yourself to damage and you are never looked in combat with a vehicle so yes you can be shot. However if your opponent doesn't move or can't move his vehicle out of base to base, during his assault phase you are considered to be in combat with the vehicle and get to hit it again.

When assaulting a vehicle try and position your charge in such a way as to use the vehicle as cover, you may get a wrecked result, meaning the vehicle stays put and is essentially los blocking terrain. Also you can set up some nasty multi-charges by declaring on a vehicle and sweeping into other units so long as you position yourself properly. For better or worse 40k has become a can opener game, make sure you aren't leaving tools in your tool box to open that can, sometimes it just takes a fist.