Yes. A firearm (as opposed to a compressed gas gun) is usually loaded to not quite burn up all the powder to increase propulsive pressure in the longest barrel it's usually used in (I know, not always, but as a general case for off the shelf), Thus, a 2" .38 is about as accurate as a thrown rock as a bullet at ranges over knife fighting range, while a 4" Model 10 S&W will center punch you at over 50', IF you can shoot it. The muzzle velocity will be higher in the longer barrel, with less muzzle flash.

NONE of this applies to an airgun whose gas pulse is used up in the shorter barrel. If there's still useful pressure, the longer barrel will be better, but we are talking about a jelly bag for a projectile here, not metal, and I'm sure surface irregularities are huge. These are NOT accurate shooters in my limited experience, and I've shot a $1000 paintball gun with another 400buck worth of tweaks to it by a "gunsmith"...