If you have a micrometer, take the measurements of the spring (the inside diameter you can measure using a wire gauge.
www.LeeSprings.com has all kinds of springs, possibly the right outside diameter. Pick the length you want and order them (you'll have to order 10, I think). I suspect there would be a market here on the site for those springs. I wish I'd thought to do this when I was hacking things.
As an example, not that this is the right size, a 0.040 od .350" long spring would be $5.90/10. It would have a spring rate of more than 2.5# per inch. Plus shipping.
You can also call Brownells and ask for the USPS small parts shipping price.