Is Your Scope Really Squared on the Rifle?

            When I was a teenager, mounting a scope on a rifle was merely a process that involved throwing the scope into the rings, eyeballing the crosshairs for "squareness," and tightening down the rings.  I mean, when one's average shot was less than 100 yards, it really didn't matter too much if the scope was actually squared or not.  Or, did it?  Honestly, I had no concerns back then, so I have no clue now if it mattered.

            As I aged, I transitioned from my first rifle, a sporterized 8 X 57mm Mauser, to the first rifle I bought with my own money, a Ruger M77 in 7mm Remington Magnum.  As this was the only rifle I owned when I was in college, I used that rifle on EVERYTHING, from groundhogs to beavers to hogs to deer.  I mounted a fancy scope with a drop compensator on that rifle (I still own it), but I missed "things" out at 500 yards, even though the analog computer in the scope predicted that the shots should hit their mark.  My shooting abilities had grown with age, but my scope mounting abilities apparently had not.  I still threw the scope into the rings, eyeballed it, and headed to the field.

            Alas, I didn't lose hope, as help arrived in a tiny and very inexpensive product by Wheeler Engineering designed to make mounting that scope easy, fast, and, best of all, level!  The product is called the "Level-Level-Level Crosshair Leveling Kit" (Wheeler Engineering #: 113088) and it sells for about $20.  The kit comes with two levels that are magnetized (which, by the way, really isn't that useful, as the scopes and many bases are made of aluminum).  The larger of the levels is designed to attach to the rifle on a flat surface so that one may level the rifle.  I have found that many of today's rifles don't have a flat surface on which to mount the level, so I typically use the flat surface of the scope base, which is attached to the rifle, to level the rifle.  The smaller level is then applied to the elevation turret of the rifle.  In theory, one may then rotate the scope until both the scope and the rifle are level, thus ensuring that the crosshairs in the rifle are squared to the plane of the flight of the bullet.

            So, now that the scope is mounted to the rifle, how can one check that the scope is truly level?  The best way, of course, is to fire your rifle at different distances, say 100 yards and 600 yards.  The first step is to zero your rifle so that it hits the center of the target at 100 yards, and then adjust the elevation on the scope so that it hits the center of the target at 600 yards, WITHOUT touching the windage turret.  Drive back to 600 yards and let fly.  If the bullets strike the center of the target at both distances, your crosshairs are centered.  Naturally, this has to be done on a day with no wind.

            What?  You don't have access to a 600 yard range, or you can't seem to make it out to the range on a windless day?  Fear not!  You can do the same test on your 100 yard range by simulating a 600 yard shot.  First, make an inverted "T" as shown in the picture below.  In this instance, I fired two shots at 100 yards (Numbers 1 and 2) without adjusting the windage, resulting in a 0.071" 2-shot group.  I then adjusted the elevation and windage (shots 3-5) until the scope was centered at 100 yards (shot 5).  Finally, I adjusted the scope's elevation knob up 11½ minutes of angle (MOA), which is 92 clicks on my scope (⅛" at 100 yards), to zero the rifle for a 600 yard shot.  I then fired a 3-shot 0.404" group. (The holes covered by the tape are a different load that I was testing).  In case you're wondering, the load used in this test is .223 Remington, PMP Cases, Wolf NCSRM primers, 23.8 Gr. IMR-8208 XBR behind a Berger 70 Gr. VLD bullet fired form a Winchester target rifle.  The bullets like to be in the lands of the barrel, and result in 3088 ± 18 FPS.  And, by the way, if you're worried that those Russian-made, cheap Wolf primers aren't any good, I suggest you try them.  They're great!

            Note that even though I used the Wheeler Engineering Level-Level-Level tool to mount the scope, I am still about ½ MOA to the right when the scope is set at 600 yards.  I hear you asking, "so what?"  Keep in mind that a ½ MOA alignment issue results in the bullet impacting the target approximately 3 inches to the right at 600 yards.  This would be fine for hunting at any reasonable distance, say 300 yards where the slight cant would cause one's bullet to impact 1½" to the right.  

            The rifle used for this illustration is fired exclusively in F-Class competition at 600 yards in which the X-ring on the F-Class target IS 3 inches wide.  For competition, the rifle is set for 600 yards and the elevation knob is never touched.  The windage knob is adjusted on each shot for the prevailing wind, so again, the slight cant of the scope is not an issue.

            My advice to you is that if you're planning on heading to the field to take long shots on game, I strongly recommend that you try this test before you watch that trophy trot into the distance because your scope was not squared in the scope mount.  You owe it to the animal to hit it where you aim!