Need some help with guns!

Hello there! I just joined MCreator and downloaded it. I want to create nice WW1 mod for 1.15.2 (i wanted to 1.16.4 but there's no version of it right now). I watched some tutorials and everything was good but... I want to do a reloading animation and make gun 3D. Every model maker was using blocks not small pixels that are needed to create normal size weapon. If someone can help, i will be very pleased :D

Thanks for your time

                                      Dirty Dan