Over the years, tend to toss salvaged springs into a couple of shoe boxes under my bench, afraid I can't tell you were it came from. Same over all size as the issue one, a little shorter, but seemed to be of slightly thicker wire. Using a power adjuster/spring guide.
Pellet used for those tests was the inexpensive Crosman HP's (14.3gr.). My opinion was that the rifle suxs at that setting, way too much work pumping it up to 2K just to get a dozen decent 26 foot pound shots when you can easily get TWICE that number of good 21 foot pound shots.