Everyone sees open sights differently and for someone else to set your sights through their eyes is a waste. Before you go adjusting your sights make sure the guns are shooting CONSISTENTLY. Even if they are off for you they SHOULD shoot all rounds into nice tight groups. If you have open groups then it ain't just the sights. If you can shoot nice tight groups just not to where you want them (in the bullseye) then bring the gun and targets to a person who is familiar with adjusting them. Re-shoot at the same distance with the same ammo and see if that improves things.
I agree with more with the statement above than the statement below. Tight groups not on point of aim suggest either:
1) you are a decent shot who is doing everything right and the sights are actually off; or
2) you have a flaw in your technique - but are very consistent with it (i.e. you put too much finger on the trigger and pull the shot to the right consistently every shot, or you tighten your grip just before or as the shot breaks and put the rounds slightly low and left).
If sighted in by someone else, they still may not shoot right for you. It depends on whether the other person holds the gun very similar to your way, including grip strength, hand position, size of hands, etc. The gun recoils differently depending on these variables, thus affecting point of impact.
This is all true, but more often than not it reflects flaws in the shooter's technique. If this wasn't the case you'd seldom if ever see fixed sights on a handgun. They work well most of the time, provided the shooter knows that he is doing.
You will see variation with factory fixed sights as they are often regulated for the recoil of a specific load. For example, most .38 Specials shoot to point of aim with full power 158 gr loads and will shoot low with loads using lighter 110, 125 and 130 gr bullets
You may also see some minor right of left windage error on revolvers due to the barrel not being perfectly timed and/or not being perfectly aligned in the frame, both of which move the front sight slightly. If you've got a revolver that shoots excessively right or left, send it back to the factory. They'll most likely mount it in a fixture and then rap it with a mallet to tweak it a bit. It's not a technique for the non-expert.
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Unless you really are a good enough shooter to eliminate #2 above as an option, you are better off having another very good pistol shooter shoot it and give his or her opinion before you blame the sights.
If not, you may find that if your pistol was shooting to the left "because the sights were off", once you develop a better and more consistent grip, the pistol will now be shooting to the right - and you'll be tempted to claim the sights moved.
better solution might be to buy a sight pusher and do them yourself. That would probably be cheaper and provide more satisfactory results.
For pistols with drift adjustable sights this is the best way to go - once you've eliminated shooter error.
You can be much more precise in the adjustment with a sight pusher. Also, if you have a set of calipers, are not math impaired, and know how far off center your groups are at a known distance, you can calculate exactly how much you need to drift the rear sight to get the center of the group on point of aim, make a single adjustment and just verify it on the target.
