Assuming all the scope hardware is tight and properly installed, sighting in a scope can be accurately accomplished without the use of expensive bore sighting gadgets.
There are several basic and very effective methods that have worked 100% for me over the years.
The first, and probably the most commonly applied method is to start at 25 - 100 yds., and if the rifle is on the paper at all, simply adjust the windage and elevation until your sighted in at that range. Then step it out to the distance desired while fine tuning as necessary. However, if the rifle isn't on the paper at all, bore sighting it first to get it on paper will be necessary. Adjustments will correlate according to how far away you are. If for instance you are 25 yards away, each moa will have a value of .25" (1/4"), .5" (1/2") @ 50 yards, .75" (3/4") @ 75 yards, and 1.0" @ 100 yards.
As noted above, using a stable rest or bags, remove the bolt and look through the bore at 50 - 100 yards. Locate the aiming point on the target through the bore, then adjust the windage and elevation until both the reticle snd bore are centered on the target.
And another method that works well also, is to turn the windage and elevation turrets until they stop, don't use brute force when bottoming out, stop as soon as you feel resistance to avoid damaging the the optic. Then from stop, count how many clicks to the opposite stop, devide the number of clicks by two, then bring it back to that number. In other words, if stop to stop is say 28 clicks, you would turn the turret back from stop 14 clicks, that would be center. Do that with both the elevation and windage, shoot one at the target, it should at least be on paper and then adjust as necessary for the distance desired. This has worked extremely well for me, but if the receiver, bases, or rings aren't centered to begin with, this method may not work very well and may require close distance papering it at 25 yds. to accomplish sighting it in, or by using the first method above.
If none of the above methods are effective, you'll need to start at a distance that at least gets it on the paper, 10 yds. should be close enough to accomplish this, then take it out in 25 yd. increments, adjusting until sighted in to the desired distance. I can't ever recall having to resort to this method, but my brother in law once had an old Mauser he had tapped for bases, but it wasn't done with much precision, so it required having to start at extremely close distance.
GS