http://www.airgunforum.ca/forums/topic43890.htmlThey are hardened, you have to grind them.... I managed to get rid of half the weight eventually, but you can start with a stock one.... I notice I didn't mention in that thread that I later lightened the hammer to gain even more shots, so it's not necessary.... You may be able to cut a stock spring enough, but it will end up rattling around loose.... I also note it was a 2289 spring, not a 2240.... The key is to get the pressure down under 500 psi....Here is an alternate setup I made, with the regulator built into the valve for a Disco....It uses a Ninja piston and spring, in a new valve front end....As with most of my stuff, it never found anyone interested in making it....Bob