You can easily make snap caps with fired resized cases. Seat a bullet in each case and fill the primer pockets with cyanoacrylate (super glue) OR if you are mixing up general purpose two part epoxy for carpentry work, use some of that. The latter option is better because the product is less runny.
When your chosen product has set, trim it flush with a snap off knife. You should also drill right through the case with a 1/8 or 3mm drill bit and clean up the hole edges with sandpaper. 80 grit is suitable.
Do that and you will have drill rounds that both last forever and … are instantly differentiated from live safety ammunition.