The P-47 models didn't have 425 rpg. The D11 didn't, the D25 didn't, the N didn't, and the M didn't.
One single group used the overload ammo load solely for ground attack and strafing. These would be late war D-40 types (or close enough), so if it must be left in-game, leave it only on our D-40. Remove the 400-round option on the other craft.
We have no gondolas on the 109F and no gondolas on the 109K4, because frankly these planes did not use them.
Our P-47s did not use this ammo loadout either, and I'd wager a pretty penny that 90% of all sorties use the overload ammo (at least... the way they spray ammo from 2k out on end seems to imply they're not worried!
).
I've used it myself, more than enough. It's nice. It's just totally inaccurate.