Well, to answer your question....yes, I believe it's necessary to level the scope. Let me explain why. I was shooting at a friends neighbors place last summer, where he has a range that stretches out to about 700yds. After looking through my scope, he told me the reticles are crooked, and asked if he could show me how much...of course, I agreed. I ended up looking at a farm gate out at about 600 yds., and then he told me to keep the scope on the gate while he loosened the rings, and spun the scope to level.....by that time, after keeping the rifle steady, the reticles were sighted in on a spot about 20 some feet away from where it was before :shock: !!! Now I'll explain how he showed me to level a scope, and shoot a leveled firearm. Go to wally world/kmart/etc..., and buy one or two of the cheap dollar or two levels(you need two of the green "level" tubes in order for this to work). When you get home, carefully break the plastic around the tubes/slide them out/ or use a dremel tool to cut them out....it all depends on the level you bought. Next, put your gun in a rest/vise, and put one of the levels between the scope, and the rail in one of the extra grooves in the scope base(it wedges in tight enough that it won't move, even when shooting). Then, put the other one on the top adjustment turret on the scope so that it points side to side. Then it's as easy as tightening the whole shoot and bang down, being sure to keep the rifle and the scope levels level the whole time. When completed, just keep the level that you used between the scope and base there, sticking out to the left side of the gun if right handed, or right side if left handed. Then it's just a matter of opening the eye not looking through the scope, look at the level to see if it's between the lines, and taking a shot. Not much sense in leveling the scope, if you don't level it at the shot as well. I did read somewhere that if your gun is canted 1 degree off of level that the shot will be inches off of point of aim. So yes, I do believe that it's necessary to level it, and at a dollar or two, this method is much more economical than those fancy bells and whistles levels you find in Cabelas for $20+. Hope this helps ya out, and the length of the post wasn't too painful :wink: .
~~~Cattleskinner