This is a collection of dummy rounds for various common calibers.

I did not design these. The original models are from Thingiverse user Spearmountain. I simply collected them and added engraved markings on the side of each case, so that when displayed, shown, or given to others, the caliber can be easily identified. (To be fair, even for veteran shooters, most cannot name every cartridge just by looking at them, people still need to look the hemispherical mark near the center of the case. I made the marking on the side of the case for easier identification.) I also slightly increased the bullet’s dimensions to 101%, because when printed at the original size, the bullet tends to fall out of the case too easily.

There are 4 versions:

First, choose if you want the bullet (head) to be separated or not.

1. Separated version – The case and bullet are separate pieces, so you can print them in different colors and assemble them (which looks nicer and more realistic). *You do not need AMS, I colored it differently just for show*
2. All-in-one version – The case and bullet are a single piece, making it easier to print.

Then choose if you want the text to be engraved or extruded.

1. Extrude - that means the text is extruded outward, and the text extrude is beyond the overall size of the case wall. 
2. Engraved - that means the text is indented/recessed inward, and the overall shape/dimension of the bullet is not changed.

However, the text in the engraved version will not be as easy to read as the extruded one. Especially the corner/edge of the text. In exchange for the benefit of no change in the dimension of the bullet casing. 

Please note:

1. These are not suitable dummy rounds for dry fire practice. Using them this way may damage your firing pin. (I’ll repeat: these are not dummy rounds for dry fire!) The original author has a proper dry-fire-safe version available on his page linked above. Since most people don’t need this many different calibers for dry fire practice, it’s better to download only the cartridges you need, directly from the origional author.
2. I highly recommend printing the case first, then the bullet. and DO NOT immediately remove the bullet from the print plate after printing—this way you’ll know which bullet goes to which corresponds case. (The cases have side markings, but the bullets do not.)