thanks for the welcome! I got the spring from ebay from this guy http://www.ebay.com/itm/Spring-to-re...4&cmd=ViewItem
and there is another guy on ebay that sells them but this one said it ws designed by a gunsmith and was made for the sigma. The other guy probably sells the same spring but I guess I liked that this guy mentioned gunsmith and "designed for the sigma". The hiviz sight I got from Amazon http://www.amazon.com/gp/product/B00...ls_o00_s00_i00
and basically, the old front sight comes off by grabbing it with a pair of pliers and twist it off or you can salvage it (like I did) by using a pocket knife or small flat head screw driver and prying the glue off from the underside of the slide. Actually, it's not glue, the site is pushed in and then the melt the underside of it and thats what holds it in place. Then Sigma and the Glock both have an oval hole cut in the slide for the front sight, the only problem is that the Glock's oval is larger so you have to file down the oval "foot" on the bottom of the new sight to fit into the Sigma slide. There is a very nice detailed write up with pics on another forum but I don't know the rules about posting links to other forums websites on this forum. It is usually frowned upon and I don't want to wear out my welcome on my second post here but I will PM you the link. If you have a Dremel and have a steady hand it is really quick and easy but even if you just have a file it would still be simple.