I have been re-reading the 40k rulebook again to fill in the gaps in my rules knowledge. I was looking at the vehicle section and found another obscure little gem. AP - gives you a -1 to your vehicle damage rolls.
Sure there are not many weapons with the strength to penetrate armour 10 that are also AP - but there are a few and well you never know when that means your raider survives instead of an immobilized or wrecked result.
Here are a couple of examples of AP - weapons:
Shatterfield Missiles S7 AP -
Deathwind Launchers S5 AP -
18" or less range conversion beamer S6 AP -
Death Spinner S6 AP -
Punisher Gatling Gun S5 AP - (you survive 20 shots from this then paint your Raider gold)
Ripper Guns S5 AP -
I am sure that I am missing a few and many of these you are not likely to see on most battlefields.
Kill the Mon Keigh or at least torture them for a while!