Those generic BDC reticle scopes work in inches of drop...they're not caliber or rifle specific.
My Vortex works, properly only at 12x magnification, in inches of drop...the first dot is -3.5", the 2nd is -7", etc. So you need to shoot a drop chart then use the dots accordingly(and approximately). They work well to a degree but they are not entirely precise. I think for long ranges(+300 yards) the BDC is a good way to go, but you gotta figure out your drop chart and use it properly. Hopefully that makes sense. It's not a rifle or caliber specific. It's just as simple as it sounds...if your gun shoots 3.5" low of -0- at 350 yards, aim with the 1st dot and so on and so forth. You just got to make the main crosshair dead zero at a certain yardage and go from there with the dots.