by Dave Campbell - Tuesday, April 17, 2012
Yesterday I was mounting a couple of scopes on rifles I plan to use on an upcoming varmint shoot, and I got to thinking, “How many times have I done this?” Hundreds, to be sure, and yet I am still learning.
Here is where I am regarding scope mounting: Arguably the most important basic fundamental is degreasing everything involved with mounting the scope—and I mean everything…right down to the threads in the receiver that are used to mount the base and the screws that go in them. I use brake cleaner because it evaporates quickly, and it cuts every kind of oil, grease or wax and leaves no residue.
Since most of the scopes I use are on loan—as are the rifles—I usually do not lap the rings because everything will be returned to the manufacturer. About the only time I lap the rings is on a personal varmint rifle unless there is some anomaly in the system. Scope-lapping kits are available from Brownells or Sinclair International, and both do a fine job. Be careful when lapping, however. If you get too enthusiastic it isn’t difficult to lap the rings so well as to make them unable to hold the scope tube.
The rings get a pinky-finger wipe of rosin on the inside to help grip the scope tube. You don’t need much; just enough to give it a sort of brown haze. I have never had a scope slip as long as I have used rosin.
Again, because most of the scopes and rifles I use are on loan, I rarely use a scope level. Setting the rifle in a rifle vise and plumbing it by eye works OK much of the time. There are a number of scope levels on the market, but for those occasions when I go through that drill I use a pair of Starrett 98 machinist levels I have on hand from my machinist days. As you level the scope, check the fore and aft position to maximize the full field of view.
It is important to progressively tighten the ring screws in an opposite, crisscross pattern to keep the scope tube from rotating as you tighten. For years I did it by hand, and only a couple of times did I break a screw. Nowadays, of course, I use a torque wrench from Wheeler Engineering. Anything from 15 to 20 inch-pounds is adequate.
Bore sighting helps save on ammo. In the old days I’d set the rifle with the bolt removed on a box with two Vs cut into it, find a suitable object somewhere around 100 yards away, center it in the bore and adjust the crosshair of the scope to coincide with the object. That will work, but it’s imprecise and generally a pain to do. There are a number of boresighters on the market that make this task a whole lot simpler. A quick tip: Center the elevation and windage adjustments prior to bore sighting so that you have a maximum amount of adjustment. To center the adjustments, run each knob to its stop, count the number of clicks it takes to go back to the other stop, divide by two and go back to the halfway point.
Like I said, I am still learning, so if you have any suggestions or tips please feel free to post them.
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