Darn!! That's too bad. It would be nice to be able to upgrade an older pistol with a part from a newer one, a part of a different design that would affect the operation of the gun. I like my Glock as it is, but I notice that my XD40 with the double spring design is a softer shooter than my other pistols. Anyway, someone will come up with a cheap version I'll bet. I know there is a hydraulic type out there now, but it's over $150. Sure can't pay that for a spring. Have a great day and thanks again for checking on this for me.