[baryon]

Hi,

If we eliminate the effect of the shooter, ammo and wind, what else affects the accuracy of semi-auto?

Is it the barrel to slide lockup, barrel rifling or something else?

[jim147]

Consistency of lock up plays a big roll it a pistol shooting to the same point each time. Tighter pistols tend to be more accurate because they don't have the excess clearance that would allow the barrel to lock in a slightly different place each shot.
Production pistols are made looser for reliability but most shoot plenty accurate if you keep all the other variables in play.

[makarovnik]

Trigger pull and smoothness.

[Disaster]

Hmmm....lets try it in order of importance.

1. The operator. Smooth trigger squeeze. Sight alignment.
2. Consistent barrel to slide lockup in a Browning design, consistent slide rest position in a blowback.
3. Good barrel, clean rifling and even crown.
4. Good ammo. Symmetric bullets. Constant bullet and powder load. Consistent bullet seating.
5. Clean feed ramp that doesn't mar bullets when loading.
6. Good sights.
7. Good trigger, crisp break and consistent efforts.

The last two can be overcome by better shooters.

[eatont9999]

What is a really accurate pistol that can be had for a reasonable amount of money and is available to the common person? Not including revolvers.

[Disaster]

It depends on what you mean by "really accurate." Like you inferred, revolvers are generally more accurate than autoloaders with locking breech or blowback designs. Fixed barrel semi autos, with the sights attached to the barrel or fixed receiver are every bit as accurate as revolvers. 1911's can be "accurized" to be quite good.