Rufus... did you count the coils? Not trying to argue with you just curious. If the spring actually has more coils and is the same gauge wire you might have a mix up. If so it could lead to spring stack if there is not enough room and damage your bolt. The spring creates a solid column that stops the bolt before it should. This has happened a few times with aftermarket springs but not Hi-point as far as I know. I have had mix ups with springs from hi-point. They typically get it right but sometimes a wrong one sneaks in. Once they sent me a stallard JS9 spring for the C9 and It created this situation. I caught it early but it did damage the slide.
I think Moona11 might be referring to spring set. Even a new spring will become shorter after a while once installed. What I am trying to say is that the overall length of a virgin spring is not really a great way to determine strength or wear sometimes. Typically you gauge it by where/how far your brass is landing. There are three springs that can effect ejection on the Hi-point design but the recoil is the main one.