Why don manufactures use a dual spring system if they are so great?
Actually one notable manufacture does. H&K installs a dual spring system in their line of pistols. They are at this time, an industry leader using this system. This is why we don’t make an H&K replacement spring system. The rest, well, what can we say? Glock includes a plastic guide rod on an otherwise excellent gun. Others use a steel guide rod with a standard recoil spring. Although these factory springs work as expected, they do nothing to lower recoil or prevent the damaging effects of heavy slide impacts.