The first thing most people want to do with a new pistol is to zero the sights. That is, adjust the sights to match the point of impact. I have seen novice pistol shooters spend hours and a lot of money on ammo trying to get everything just right, especially on the first day they take the pistol out to the range.
Most never get comfortable that their pistol has actually been zeroed and some even begin to blame the pistol. "There must be something wrong with this pistol. It's shooting all over the place no matter what I do with the sights." they will say.
Is your skill level high enough yet to properly zero your pistol?
Before you find yourself in this position let's get an understanding of what we are trying to accomplish. By zeroing a pistol, or rifle, we are trying to predictably place the bullet at a point on a target by adjusting the sights.
As with a rifle, the pistol must be relatively stable, held on target during the process with the trigger being pressed straight back along the center axis of the pistol. This will yield relatively tight groupings of shots which is necessary to know how and where to adjust sights.
With a rifle we can securely rest the firearm on bags or a sled so that the muzzle doesn't move at all, or very little. We have three points of contact with the rifle - our right hand on the gore grip, right hand on the pistol grip, and cheek on the riser. In addition, the rifle is also touching whatever you are using for a rest.
When shooting a pistol your only contact points are both hands which are much closer together making a much less stable support platform.
With any new pistol, or one that you want to zero, shoot a few shots through it at target that is 5 to 7 yards away. If you can't group shots in a 2 to 3 inch circle, you may not be ready to zero your pistol.
A group similar to the one pictured left is what you are after. It doesn't have to be centered on the bullseye - just somewhat tight and not scatter all over the target. You need to be able to do this before making any sight adjustments.
If your shot pattern looks more like the one below, you are not ready to adjust your sights. Doing so will result in getting caught in that circle of needlessly wasting ammo and getting frustrated. Take it from the voice of experience on this one. You will make adjustment after adjustment and never get it right.
This happens because your fundamentals aren't yet good enough to consistently shoot your pistol. Believe it or not, most pistols come out of the box with the sights set correctly. One small defect in grip, trigger press, or flinching can make the pistol shoot shotgun like groups like the one below or cause the group to be considerably off center. Proper practice is the best way to correct this issue but this takes time.
If you just have to adjust your sights now and can't wait on improving your basic skills, you can use a rest but realize that shooting a pistol with a rest can cause bullet impact to be completely different than when holding the pistol normally. See the rests I recommend below.
If you plan to shoot your pistol from a rest all of the time, like in a hunting situation from a bliind, then by all means it makes sense to zero it that way. But if you will use a pistol as most of us do, free handed, for self defense training, don't use a rest to zero unless you are willing to change your sight settings as your skill improves.
What distance ?
Once you are somewhat competent with your pistol shooting ability the distance at which you should zero depends on what you plan to do with the pistol. If you shoot pistol competitions such as IDPA, you might want to use a 25 yard zero.
Whether you are using a 9mm or a 45 acp, that will cause your shots to be a couple of inches low at 10 yards. In a self defense situation that doesn't really matter a lot but in IDPA a couple of inches could mean winning or losing.
At my local pistol range, the furthest we can shoot pistols, outside of a special event, is 25 yards and it just so happens that is where I most of my shooting. We typically shoot 4 inch clay targets at that distance. This necessitates that I remember my shots will be low at closer ranges.
Below is a ballistics table of a typical 9mm load out of a pistol with a 25 yard zero.
You can see that with a 25 yards zero, you will be shooting as much as 1.5 inches low at closer ranges, but slightly high at further than 25 until you reach the 100 yards range where bullet trajectory will drop back through the zero setting. I know what some of you are thinking, but oh yes, you can consistently hit a man sized target at 100 yards.
Zeroing at 10 yards will put you just slightly low at 25 and about 8 inches low at 100. For most shooters, we are splitting hairs here. They will never shoot their pistol at 100 yards and will do the majority of their shooting at less than 25.
So every shooter needs to decide which zero distance makes the most sense for him. Actually most pistols come out of the box zeroed at 10 yards. Some pistols don't even have adjustable sights. 10 yards probably makes the most sense for most shooters.
A pistol for most shooters is a short range weapon. Most will never shoot beyond 15 yards and if it's ever used for self defense in the real world, it will probably be much closer and I can guarantee you that the average shooting won't even see his sights. He / she will be focused entirely on the target and shooting instinctively.
So don't get to hung up on getting pistol sights set perfectly, focus more on improving your technique to allow good groups with the factory settings.