Scorch comments on Anschutz rimfire barrels going from short to long:
With match rifles that use iron sights, it is a sight radius issue, the longer sight radius gives better accuracy. In a match, that is important.
True, but their short barreled versions had a long bloop tube on them so the sight radius was the same as their long barrel versions. That way, their rear sights would change point of impact the same per click regardless of the barrel configurations used. Here's an Anschutz bloop tube that adds several inches to the sight radius. A slot at its top back end aligns with a pin on top of the barrel behind the muzzle where it clamps on to. It' got a 3/4" diameter hole through it the bullets go through.
I don't think a longer sight radius gives better accuracy as the front sight still wobbles around the target the same amount angular wise regardless of sight radius. But the further away the front sight is when one's aiming eye is focusing on it, the sharper the target will appear.