I like to set everything on the scope to the middle of the travel, windage wise, and then mount the scope in the middle of the hardware screws, using a laser boresighter, indoors. Then also with the laser boresighter, adjust the elevation so that the + is the exact height of the mounted scope over the bore on the wall about 10 ft away.
That gives you a prefectly zeroed scope setting to start with. It will ensure that everything is set to center, and that you are on target with your first shot.
You can use lock-tight or clear fingernail polish then to firmly set the screws, one at a time, once you know where they are supposed to be set. That is the second step. Once all the screws are lock-tight-ed, you can re-check the settings with the laser bore sighter again.
Then go to the range and start close, but only adjust the L/R windage, as long as the high/low impact is on the target somewhere.
Your first adjustments for drop should be at 100 yards, but at that distance you normally would want the impact about 1 to 2 inches high, depending on what distance you want to zero at. Most hunters zero at 250 to 300 yards.
Note that with a 300 yd zero, your impact at 150 yds will be the highest on the target, which is the peak of the parabola of flight of the bullet.
A bullet is like an arrow, it flies in an arc. Just a very small arc for the first few hundred yards.
Fire 3 round groups, and take the center of the triangle they form, as your point of impact for adjustment. If the rounds touch, then you know that you have got a really good gun and/or you are a really "good" shooter. Rarely will they touch though, not without a lot of practice.
Once the scope is set, then clean the rifle, and bring it back to the range the next day, and see where it fires on the first cold shot, to see if there is much if any of a difference. With some guns, there is a big difference. Other guns have little or no difference. With hunting, it is normally the first cold shot that matters.
Once everything is set, at the range, the second time, then bring your gun home, and put the laser boresighter back on it, and see how far off it is from the theoretical center. There is usually a difference, since the bullet spin is like prop wash on a boat, and steers the bullet slightly down range.
Then record everything, so that you can re-set this setting later on, and in subsequent years.
That's how I bore sight my scoped .300 RUM.
Last edited by Shoobee; 01-15-2012 at 05:27 AM.