I just purchased a Glock 21 SF. (It does fit my hand better than my Glock 20). I pulled out the mag springs and they are "twisted" compared to the mag springs in my other Glocks. In other words, the springs do not lay flat on the table. If you lay the top part of the spring flat on the table, the spring lifts off the table starting about mid-way through and kinks off to one side. Can someone disassemble their 21 SF mags to see if this is normal? Thanks!