I have noticed this as well. Snuck up on a 47 while the pilot was AFK, planted a tater square into his tail section. His bird stayed in the air, and when he came back he shot me down.
IMHO he should have lost his whole tail, not just one stablizer.
If you hit just one stabilizer with one 30mm round, why would the whole tail come off? Remember, the Mk108 30mm cannon has a great deal of dispersion, even at relatively close ranges, meaning you could center your pipper on his tail, see the big pumpkin hit-sprite on his tail-section, but the round could easily have impacted on either horizontal stabilizer.
I find dead-six tater-shooting particularly difficult for this reason, and prefer to set up some off-angle to get a wing hit, if I can, especially on robust birds like the P-47.
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Ryno