here i have a spring i designed for a AICS .308 magazine. i found a file for this magazine and printed it. but didnt come with a spring and i didnt wanna buy one so i made one. i printed this out of pla and it worked well. as you all know, plastic has a memory. and after conpressing the spring a few times with a full magazine, it starts to loose its “springiness”. this may be different if another plastic is used. still in the testing faze. updates MAY come.