1" at 10yards is about 10 MOA. Five shot groups of that size should be possible with a good gun, ammo it likes and if the shooter has no impairments.
As I said in an earlier post on the thread in question, a person who can shoot 25MOA (about 2.6" at 10 yards) is a good practical pistol shot. I'd say they're probably doing better than the vast majority of pistol shooters.
The difference between the two levels of accuracy (given the stated assumptions--no problem with the gun/ammo or shooter impairments) is almost always flinching/anticipation but could also be a trigger technique problem.
You can check your trigger technique by dryfiring while watching the sights. If they don't move, your trigger technique is fine and that leaves flinching/anticipating the shot as the culprit.
When I say it needs to be a good gun and ammo it likes, that doesn't mean it needs to be a match gun or match ammo.
For example, here's a group I shot offhand some years back with a stock Glock 17 and 6 different types of ammunition to show that practice ammo can actually be quite accurate and that even mixing different types of ammo on the same target can provide good results. This group was a 10 shot group shot at 15 yards and works out to about 13MOA. Best 9 of 10 were about 10 MOA.
