I think that it's important to point out that just because a spring "fits into the gun", it certainly doesn't mean that it "fits the gun". You may....(or may not)... be able to cock the gun and it will probably shoot but what good is it if the performance or consistency isn't there or the possibility of causing other damage? There are many factors that come into play regarding a guns performance and it's relationship to the spring. For a few, the wire diameter, coil count, preset, spacing, coil bind, inside diameter, outside diameter and the spring wire composition.