Quoted from gweempose:
Be careful. The plastic part doesn't snap into anything. It just sits in place and then gets locked together with the housing when you slide the metal rod through it.
It is a pain in the ass. You just have to go very slowly. I use a smaller metal rod as a place holder to line up the spring with the target face. I then carefully displace the smaller rod with the correct one as I slide it through.
Pain in the ass is putting it nicely. In my opinion, it's not worth the headache.
I found another method that appears to work exceptionally well, even on targets that might have a broken plastic tab. This method is simple and easy. And the materials are readily available.
Take a small flipper spring, stretch out a section to size, cut it, and hot glue it into the inner side of the black plastic housing that holds the target. There is a small ledge inside that the spring can sit on. Then hot-glue the other end of the spring to the target.
The hot glue provides a surprisingly strong, solid attachment of the spring to the plastic. I know this because it was not easy to remove the spring when I was testing various spring sizes and positions. When the hot glue dries, it is like a soft rubber, allowing some give, as opposed to a brittle glue that could just snap under stress. I was really surprised how good it works.
I also found just putting a single spring on one side is just as good, if not better. Here is a pic where I used two springs on each side to give an idea of placement. I ended up using just one spring on only one side, as two springs was overkill. This target has a very similar feel as the original targets that have the factory torsion spring.20190128_182736 (resized).jpg