I have a Vortex Viper HST 6-24X50 on a .223 Rem Savage Model 10 Precision Carbine. Today while I was shooting at 435 yards with consistent hits, I realized after about 6 shots that my parallax adjustment was set at 50 yards. I immediately changed it to just over 400 and shot again. After adjusting the parallax I did not touch the elevation or windage before shooting the next round. To my surprise I missed the steel completely. I repeated the shot 2 more times with 2 more misses. I changed the parallax back to 50 yards and fired another 3 round group that all hit steel and were a little less than 1 MOA. I was shooting alone and did not see where I was missing, but I was wondering how the parallax adjustment could make my shot change that much? Thanks for the info in advance.