Yes. Some guns, and some gun+ammo combos, are inaccurate. Guns are machines. They wear out (rarely) or they are machined improperly (less rarely). Some guns just don't like certain weights of bullets, or even certain brands.
To really tell if it's you or the gun or the ammo will require you to change the variables one at a time. Have someone else shoot the gun. You shoot a different gun. Try a heavier or lighter bullet, etc.
With a pistol, provided there's not excessive wear or tolerance slop that allows the barrel to wander about compared to the sights, the answer is no
A short sight radius with short barreled pistols and revolvers will inherently have a larger pattern as the circle probability of error increases in target sighting precision.
That's simply wrong. The cut of the chamber, the rifling, barrel crown, consistency of lockup, etc. all have a role in accuracy.
User dependent. You can shoot a snubby as accurately as a 6" revolver if you know what you're doing. You can't shoot it as accurately as quickly, but there is nothing inherently inaccurate about a shorter sight radius. Certain pistols are actually more mechanically accurate in shorter lengths, the Glock 26 being an often cited example.
I've been down the path of testing repeatability of human visual acuity for unaided inspections and alignments in other technologies.
I have a S&W Model 659 that I've been training with, and after about a year of shooting with this gun I can not hold a tight group even at relatively close ranges. I squeeze, not pull, and practice dry firing to lessen barrel movement during trigger squeeze. Any ideas, or just keep training?
If you believe... "Snubbies with 2-3" barrels are more for up close and personal short range center of mass use under 10 yards than driving nails at 25 yards." then I'd recommend you take a snubby course at Sand Burr. Theory is great. Go to the range and test it. I bet you'll find you end up shooting a 2" just as well as you shoot a 4" or 6"...just slower.
Sight radius plays into speed at which you can get acceptable sight alignment, and also plays into velocity which helps with reducing the need for adjusting the sight picture for bullet drop. If you have a good grasp of the fundamentals, you'll get the same sight wobble with a 2" you get with a 6" if you aren't pushed for time. The longer sight radius is more forgiving of user error, and is faster to acquire at any skill level, but is not more accurate.
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