I would ask how is it you are aligning the sights when shooting at the different ranges ? Mine is dead on after I fine tuned it after taking it out of the box and tearing down and cleaning it. I do this with all my new firearms. It only took a couple of magazines to get it zeroed to my way of framing my sight picture. Lot of good suggestions here so I would try them all and go from there. I would also suggest you try several different brands of ammo as some has the reputation of not being really great quality control. My firearms both long guns and handguns love the Hornady brand and for my long guns they will shot great groups an to get any better I simply use the Norma brand. Norma is a bit pricey but I only use it for hunting when I know I will be shooting long distances. I have a Swedish Mauser model 96 that I have set up to shoot 0-60 yards and then I have a Yugo Mauser model 48 that I rebarreled and rechambered for the .300 Win Mag that is set up for shooting 600-1,000 yards. My best friend and shooting/spotting partner and brother Veteran died in may of 2012 and until his death we were shooting in LRRP matches and using his off the shelf Remington model 700 SPS in .308 and the two rifles I mentioned above. We were very competitive with both active duty military and LE snipers some who were shooting $5.000.00-$7,000.00 rifles. I will tell you that the Nightforce brand of rifle scopes are well worth their cost.