This is a spring for a 30 rounder pmag or any kind of ar mag.
With this style of a spring you can just contain about 20-24 rounds in the magazine however if you make the magazine longer you could have the full 30 rounds in.
I am up for idea´s to make it better.

you can also use normal PLA or ABS or PETG however that will make your result different.

Also a tip: put the spring into water after printing for some time like 1-2h after that the plastic is hydrated that will help the spring to be not that brutal.

Thanks!