[Backis]

Regarding the slat armour, this is how I have understood the matter.

The main intention with the armour is probably not just to increase standoff distance as the methods I mentioned in my earlier post. Most modern HEAT rounds retain coherence of their penetrator stream long enough to penetrate most AFV through both sides from a flanking shot, thereby pretty evidently proving that a few decimeters more standoff will make no difference for initial penetration.

My take on the slats as used today are that they are mainly intended to "disrupt" the warhead before they detonate. This is mainly effective against the older type or HEAT rounds such as those used by Iraq (main HEAT threat being the PG-7 and perhaps some PG-7V). This type of protection is effective since the piezoelectric fuze only covers the tip of the forward cone of the round. If this misses the slat the remainder of the warhead will strike them and break up, severely degrading its effectiveness. If the fuze strikes the slat the round will work and probably retain almost full effect regardless of the standoff distance.

However, modern HEAT rounds are usually fuzed over their entire front(f e the AT-4 is) and will detonate when striking the slat, negating any advantage other than the increased standoff (which I hold as rather insignificant).

Add to this that the rounds used in Iraq are mostly really old and crappy examples, having been stored a decade and half longer than they were ever intended to. Some AAR's report a quarter to a third failing to detonate at all, how well those that DO detonate actually work one can only speculate.