psycix wrote:if the plate would be part of the projectile, it will have a larger impact diameter, thus no longer being a sabot round.
Just a matter of semantics, but what you're saying is NOT necessarily true.
Everyone is familiar with the term "discarding sabot." That brings up a question: Is there such thing as a "NON-discarding sabot?"
As a matter of fact... Yes, there is.
They're primarily used in aircraft in anti-armor kinetic rounds. The problem with discarding sabots is that they tend to get sucked up by jet engines (that's bad, mmmkay?). Solution? You make a kinetic round with a sabot that stays with the projectile until impact. A non-discarding sabot.
At impact, the penetrator does it's thing while the sabot gets stripped away by the target's armor.
In any event, the point is that anything introduced into the bore to allow a sub-caliber projectile to be fire is by definition, a sabot. What happens to that sabot after the projectile clears the barrel is irrelevant to it's initial classification, but obviously determines whether the sabot is of the discarding or non-discarding type.
So... What you propose? That would indeed be a sabot... of the non-discarding type.