I posted this in a reply to a post on another thread, hopefully this may be useful for new shooters, A scope can be zeroed in a few minutes with only two shots.
* Mount the rifle in a stable gun vice/clamp system, make sure the entire rig can't move;
* Remove the bolt, barrel sight on to a target situated at the required distance, (look down the barrel and align with the centre spot on a target);
* Replace the bolt and fire one shot, if the rifle and clamping structure has not moved, all you need to do is adjust the scope settings so as the cross hairs align with where the projectile hit the target, (if you think the rifle has moved, remove the bolt and realign the barrel with the centre spot, then adjust the cross hairs to the hole in the target, you may have to use a couple more shots to check the alignment);
* Fire another shot to check the alignment.
EDIT. OOOPS!!!!! Thanks to a couple of friendly reminders form other contributors, I realised I omitted a very important point, if you are using a heavy caliber, don't completely prevent movement, the firearm has to move to compensate for heavy recoil or, damage will occur, if the outfit moves, simply return the cross hairs to the original point of aim before adjusting.
I have use the above method for years, it saves a lot of time and ammo, the trick is making sure the rifle does not move after the first shot is fired, by aligning the cross hairs to the hole in the target, your scope is accurately adjusted to where the rifle actually shoots, after that, any misses are down to operator error.