Rifles powerful enough to pierce the armored vehicle might be anything from 5,56 mm rifle to 100 mm gun, because they don't mention what kind of armored vehicle, from which side, angle and distance. It's a media technique similar to clickbait title - give the reader something to make their imagination go wild, while giving no concrete information.
Since the armored vehicle in question seems to be an armored van, 7,62x51 will certainly do the trick and I wouldn't bet my life on stopping 5,56 mm either.