Does it look like this...?
If so, it does appear that the top end is open. If so, and you can get it into a vise (secured at the solid
top/nut portion, not the threads) Powderman's suggestion is correct as to tap the bullet down into the case with a rod/punch, saturate with light oil, then further tap the bullet/oil-saturated powder/case combination down and out of the die.
THEN.... go get a nice/cheap single stage press and some of this stuff:
