Free: Contests & Raffles.
I would choose the 22", and not for velocity considerations. A very short, lighter barrel can be more difficult to accurately shoot offhand. It will likely generate more muzzle blast and jump. A 22" barrel is still short enough to handle easily.
18.5” barrel all day long! You won’t miss the velocity out to 150 yards but you’ll definitely notice a 4” shorter gun. I’ve had guide guns in 444, 45-70 and 450 with the 18.5” barrels and they’re a dream to carry while hunting. Bigbore rounds kill more like a muzzle loader than a high velocity round so just pick a good bullet and don’t worry about the velocity.