Can someone, please, explain the use of a 20 MOA riser on a rifle? I have a new rem. R-15 VTR with 22" bbl. Leupold VX-3 4.5-14x40 LR scope with a Vrmint Hunter reticle. I mounted this on An EGW Percision 20 MOA riser with a set of EGW tactical rings (Med rings). Perfect height for a good cheek weld. Shoots like HECK, but when I used my Leupold boresighter it said I was, about, 12-14 MOA low. HAVEN'T TRIED THIS AT THE RANGE, YET. Should I adjust the scope up or try shooting it first? Any comments greatly appreciated.