Sighting Your deer rifle.
Okay. If you have read up to this point, you know that any change in ammunition or weapon will change the projectiles point of impact. So, you now have both the weapon you will use, and a box of the ammunition you will use.
I know I probably stressed that point a lot earlier, but it is not just a major point, at this stage, it is the major point! If you have a box of 150 grain brand X cartridges, and you site in with them, but buy a box of 180 grain brand Y cartridges for your hunting trip, you are asking for trouble. I know it may sound silly, but I have seen it happen on many trips to the range when a guy at the bench next to me is sighting and practicing with a box of full metal jacket rounds, which you cannot, of course hunt with and when asked about that, he says that he is sighting in with this ammunition because it is cheaper than the ammo he will hunt with!
You have your rifle, and the ammo you plan to hunt with. Go to the range, and set a target at the 25 yard backstop. If you are doing this on your own turf, or at a buddies makeshift range, set up the same way. This is, a bench, at 25 yards from a secure backstop, where stray rounds will only strike the dirt or an impenetrable wall.
We will assume (how I hate making assumptions) that you already have either bore sighted, or used some other method of getting a pretty good idea of where the bullet will exit the barrel, and wind up at this short distance. If you are using a scoped rifle, you should already be familiar with your scopes knob adjustments and which way you need to turn them to adjust for zero.
Insert a round into the chamber, and lock it. Fire 1 round at the bulls eye, using all the skills you have learned about such things as breathing technique, and gentle trigger work. If this puts you on the paper, great! If not, you have some work to do. We will add a supplement for just such a case. Adjust your windage and elevation knobs, and fire another round. If you are familiar with your weapon, this will probably cause the next round to be dead center in the bulls eye. If it does, you will want to set a target at 100 yards, if not, continue to do the same thing until it does.
Set a target at 100 yards. Return to the bench, and repeat the whole exercise again. If you are hunting in an open area, with more than 300 yards of opening, you can set your zero to place the bullet 3 inches high at 100 yards if you like. That should give you a clean kill at any distance within that range.
I have seen several instances where friends came to the range with me to sight in a rifle, This is usually preceded by stories of 600 yard clean kills. When we arrive, and set up targets, they often ask why we are setting up at such long distances. “Why are we setting up at 300 yards?” “Well, we are not, we are setting up at 100 yards, that is 300 feet!” Most people miss judge distance. In my area, I have never seen a deer taken at a distance exceeding 75 yards.