Can i use a this in my machine

https://produto.mercadolivre.com.br/MLB-718651315-broca-longa-de-pua-26x400mm-para-madeira-makita-d-07521-_JM

I don’t find the 600mm, can i use a 400mm for my extruder??

shouldnt be a problem 🙂 just shorten the rest of the barrel to suit. You may need some more powerful heating elements if you end up with a shorter melt zone…