Actually, there are different kinds of shells that panzers used. AP, or armor piercing, do NOT make an explosion, and were used exclusively against hard targets like...other tanks.
APHE, or Armor Piercing High Explosive, which were AP shells with a HE core. These shells were meant to pierce hard targets...like tanks...and then explode once they had pierced the tanks armor.
HE or High Explosive rounds were used against soft targets, like infantry, and made an explosioon based upon the caliber of the cannon firing the shell. 3.7cm HE shells didn't make a big explosion, 8.8cm HE shells made a huge explosion.
There are others rounds, a lot in fact, such as HEAT, etc...but you get the picture. It depends on just what shell that Tiger fired. If the Tiger commander was expecting to fight other tanks, he would have his loader load an AP shell. So, to load an HE shell, he would have to get rid of the AP shell already loaded. How do you do that? Well you sure as hell don't take a live round out of the cannon. Tank crews never did this...to get rid of a round, to load a different type, they always just shot off the round in the breach, and loaded a new one.
Of course, most German tanks, used APHE, not AP, so the missing explosion is odd. However, it could just be a AP round, being fired off, to load HE rounds.
Shrugs.
It is just a game.
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34th SS-Freiwilligen-Grenadier-Division Landstorm Nederland
"Meine Ehre heißt Treue"