Using all available public data I have re-created a 3D printable M919 25 mm APFSD-T round used in the M242 Bushmaster featured on the Bradley Fighting Vehicle.
I have optimized the design to make it easier to 3d print mostly without supports (The Top Cap will need supporting) and improvised where data was unavailable. But it will print 1:1 scale with no issues. I have also included a cut-away model for the shell casing.
In the real world, the M919 Armor-Piercing, Fin-Stabilized Discarding Sabot With Tracer features a depleted uranium dart that travels at 1390 meters per second!
For transparency, it's crucial to emphasize that this is not a live round and should never be used in any firearm. This design is solely intended for educational and enthusiast purposes. (Attention CG Trader, this is not a functional ammunition piece and complies with all safety regulations.)