Here’s a nice PGU-15/B TP projectile for sale on Gunbroker:
Here’s a PGU-13/B:
The PGU-14/B projectiles come up now and then as well, although they are often more expensive. Nine times out of ten they will not have the DU core - they will either have no core or a steel core.
As Ron and Jason mentioned, inert rounds do appear from time to time. The PGU-16/B dummies are pretty common, and if you’re patient you can find factory inert PGU-15/B, PGU-14/B, and PGU-15/B cartridges. These tend to be expensive, but they are nice!
I think I have a copy of a drawing for the PGU-14/B projectile somewhere although it will take a few days for me to dig it out. Once I find it (assuming the dimensions are legible) I can forward a copy to you. Current versions of the TP and API projectiles should have the same profile so you could machine both of those from PGU-14/B drawing. I don’t think I have a drawing of the PGU-13/B however.