[reupload because of a bug of Thingiverse 09.04.2022]
I used 2 magnetics (6x3mm).
With a layer height of 0.2mm you should set up a pause at layer 19.
The last to parts of the slug are not movable because of the magnets.
The slug is 150% scaled because of the magnets.
You should print with less weight, for e.g. 0% infill and not more than 2 walls.
Magnetics that I used: https://www.aliexpress.com/item/32951137017.html?spm=a2g0o.cart.0.0.22783c00OsamVW&mp=1
If you don't have a 3D printer, I sell it on Etsy: https://www.mikebayer3d.etsy.com
The original design is from Isaiah
https://www.thingiverse.com/thing:4727448
magnetic_slug_v1.stl | 15.1MB |