Rifle Scopes, Part III: Mounting and alignment
Now that we have acquired our rifle, scope, rings and accessories it is time to mount the scope and align it so you can hit the X Ring-dead center. It is best to use gunsmith screwdrivers and related bits; otherwise you will have burrs and nicks in your craft.
Considering you have already invested a couple thousand dollars and have been patient in tooling your new prize, a little longer wait in more acquisitions will be in the long-term benefit. Excellent Gunsmith tools and lathes may be obtained from http://www.grizzly.com/. See page 289 of their current catalog. The item # H8160 at $24.95 is their 53 pc ratchet socket/bit set. I am getting serious about their Gunsmith Lathe. There is a dearth of gunsmiths in the area, and in today’s world one can make some good money as a smith. You will have to be registered with Homeland Security though. Correspondence schools are to be avoided. Seek hands on resident school course.
Our next step is to place the rifle in a gun vice, or at least sand bag it upright so that it does not wiggle around. Then with a clean gun patch and a few drops of 70% Isopropyl alcohol we will wipe clean the scope mount screw holes on the receiver of the firearm. Probably the factory has screw plugs that you will remove and place in a small film canister, or capable cup so they are not lost and can be later stored in your accessory kit. The undersides of the mounting plates-sometimes attached to the rings- are also cleaned. Factory mounts are greased and this must be cleaned before mounting.
Align the mounts over the screw holes, and one by one insert the screws gently screwing down just to hold the mount in place. Then one by one in a cross manner gently tighten, and then repeat gradually tightening again and again so that all screws are equal-as best you can make it- equally. It is also a consideration to place a small dab of Lock-Tight or similar screw thread goo on each screw that will “set” the screw in place so that the screws do not become loose after repeated firing recoil. Lacking Lock-Tight you can use clear fingernail polish- but the latter is harder to unscrew if you ever decide to change the mounts.
Next after reading the manufacturer’s directions to your scope it will probably say to hold the scope up to the blue sky and quickly ascertain if the picture is clear. If not, the base focus ring is adjusted to give a clear picture. Clean the underside of the scope with the alcohol and place it in the lower half of the rings. Next place the top part of the rings in place and repeat with the screws, carefully tighten just enough to hold the scope in place with out sliding.
The next step is critical. You need a perfectly vertical level line on a wall. Use a carpenters level. Next align the gun bore axis in the vertical with this vertical mark. This is best accomplished with a small bubble tool sold for this purpose that is placed on the receiver-also alignment cards are offered in this respect that attach to the rear of the receiver and have vertical and horizontal inscribed lines. The base of the mounts-if flat makes a good base for this procedure.
Now rotate the scope to align the internal cross hair, or post, to the wall vertical line. Hold the rifle comfortably and determine if you have about 3 ½ inches between your eye and the scope eyepiece. If you feel cramped you can always add a rifle butt plate extender pad. This gives you a longer pull and long armed big men usually add this feature.
Recheck the vertical alignment. If you do not have the scope in a perfect vertical alignment with the bore axis you will always be firing on a “canted position” and as distance increases you will constantly be missing the X Ring and no amount of internal cross hair adjustment will correct this. See the lead in picture as an example of a canted scope alignment.
Tighten and recheck as above.
Your next step is to align the scope internal cross hairs, or post, to the bore axis. I have used all sorts of devices over the years and the quickest means I know of and the most reliable is to purchase for your caliber rifle a laser cartridge that inserts into the breech just as if it was a live cartridge which projects a laser beam right down the center of the bore to a target.
There are variant other similar options but the cartridge model, which is relatively inexpensive, offers the most accuracy and convenience. Clean out your gun bore first.
Also noted is that you will use this device when buying a used scope mounted rifle to verify accuracy.
The factory laser will offer suggestions and it is best to follow them. This entails in setting the scope mounted rifle in a gun vice, or sand bagging it rock steady and uncanted in the true vertical the laser beam is focused on a wall and the elevation and windage (horizontal deflection) adjustment knobs on the scope are tweaked to align the cross hairs accordingly. It is wise that after you have made this basic adjustment to then in a twilight time aim the laser at a distant target of say 100 yard make it rock steady, remove the internal laser and fire three shots at a test paper target sold for alignment purposes.
The first shot cleans the bore. The next two will give you proximity of where the true bore axis and scope axis is. You ought to be very close. Lets assume you are two inches to the left and one inch high. You need to correct by adjusting the scope knobs in accordance with their mil correction. Lets us assume you have a one-mill correction for one hundred yards. So you click right two clicks- that’s two inches and one click down, that’s one inch. Fire again. If you have a ¼ mill correction scope you will make more clicks up and down but the final adjustment will be more critical accurate. I like the 1/8th mill correction.
The internal laser is to get you on target. You can AFTER aligning the scope to the gun bore place an external laser sight-usually installed on the scope itself. Recall that NIKON makes an internal laser in their scope too. In these scenarios the scope is dead on and the external laser is ADJUSTED to the hole in the target while the scope is held also on that hole. Now you can place a laser beam on a target and otherwise place the bullet exactly therein. We will come back to this topic later when we are talking about actual shooting in the field.
The last step is to look at the scope turret knobs. Note that there are tiny adjustment screws holding down the marking numbered ring. If you loosen these screws you can SLIP the ring to a ZERO position. Then if your scope is out of alignment you can check the ZERO quickly to see if anyone has messed with the turret knob adjustment; fiddlers will do this. Also when we are in the field if you are working from a ZERO alignment turret knob in elevation or deflection you can easily record bullet impact with varying ranges and wind patterns easily for future reference in your rifle log.
This is especially important to record as you may be firing at all sorts of ranges and different bullet weights, powder variants from different manufacturers etc. As we progress when you have determined which manufacturer you find the that your firearm prefers you can get in the recommended wear in 200 rounds for a final critical scope adjustment and then align the external laser again.
Next in this series we will take you afield for the different wind patterns, gravity, target movement, time of flight, temperature gradients, humidity, and such important facts to make sure you bring home that trophy you have always dreamed about.
While you are getting aligned we will take a break. In the next article we will talk about snakes, then get back to rifles-soon.
Are you enjoying this series? Eventually I hope to offer this, and others, in a DVD format. Tell me what you want to read about.
CIOPYRIGHT: 2010, Back2theLand.com, Mark Steel