sfmedic says:
If everyone fires the gun and it doing tight shot groups in the same spot then adjust the sights (if you can or if you can without screwing up the gun)
Not everyone sees the sights in the same way. My friend, the late Cecil Vick, had a S&W .357 Magnum, pre-Model 27, with 8 3/8" barrel. When he had the gun sighted in for him, I could never get close to the target. Same for him and my Super Blackhawk. We shot nearly a foot apart at twenty-five yards.
Likewise, my son-in-law could never hit with my Super Blackhawk, nor could I with his. Yet all three of us were very good shots with our own guns sighted in for our eyes.
Further, after I had cataract surgery several years ago, I had to re-sight all of my own guns.
And:
are you going to adjust sights on every gun he buys from then on ?
Well, certainly. I adjust the sights on every one of my guns as required to hit to roughly three inches high at twenty five yards. Most of my Rugers I sight in at twenty five yards with my pet load. I then place the rear sight about mid-height then file the front sight down to match. This allows me enough elevation to adjust when changing to a different load.
And, further:
never adjust an accurate gun
No matter how accurate a gun is, if I can't hit with it, I'm going to adjust the sights!
Bob Wright