Also you can take an angle grinder, mount a thin cut off wheel on it and cut the spring. This can be dangerous but , take your time and wear proper safety gear. Main thing is to keep the cut area cool .
I used water and a can to splash it.Once cut, the real work starts .You have to polish the string nocks perfectly or they will saw your string off quickly.Lay out your cut first and try to get it perfect. When done , I polished the entire prod. Don't leave any little snags on it. They don't hurt the prod but they demolish anything that touches them.There are complete "how to's" on u tube for doing this.Oh ,just as a side note, a sanding grinder pad will cut as good as a grinder disc,but it makes far less heat , which is your enemy.I'm talking for polishing here. A hack saw could also be used. No matter what is used , you need an extra dose of patience, don't try to hurry any operation.