The milspec rifles have an interesting history about them that does make them unique. Whether unique is good or bad will depend on each person's perspective in this case. The single big thing that makes the milspec unique, and consequently gives it the milspec name, is the barrel. The way the milspec came about, as told to me by a Remington LE division employee, was a byproduct of the M24 production line. There are specific tolerances that each M24 Barrel must achieve in order to pass inspection. As is normal in any production line some of the barrels will not meet those specifications and Remington would toss those barrels into the "no-go" pile and discard them (I am not sure where they used to go from there). It turns out that someone had the idea of taking those barrels that did not pass inspection and re-contour the barrel to the standard Remington heavy barrel contour, mount it to a Remington 700 stainless action, and call it a "Milspec" rifle.
Since there are not a large number of barrels that do not pass inspection the rifle were considered a limited edition rifle.
