.50 Cal "bullets" for Umarex T4E TR50/HDR50 CO2 revolver

Simple .50 Cal "bullets" for Umarex T4E TR50/HDR50 CO2 revolver. One version is solid, the other has a spherical hole in which a 6mm airsoft BB can be inserted.

PS. I finally managed to "field test" the bullets, and to my disappointment, the accuracy was awful (or better said... garbage!). I could not hit a melon from 4m away!
I don't know if it's the design or the print quality or maybe they were simply too lightweight, but take this in consideration before printing this item!