There's a velocity limit when using black powder--maybe somewhere around 1500fps, I don't know the exact value. It's the same with smokeless powder--the limit is just much, much higher--somewhere between 5,000 & 6,000 fps.
Before smokeless was invented, if you wanted more power, you had to go with bigger and heavier bullets because you weren't going to push the velocity up past the limit. This led to some real monsters that were made for hunting in Africa. Bore diameters could exceed 1" and the recoil/blast sometimes caused the shooter to bleed from the ears.
Before smokeless was invented, if you wanted more power, you had to go with bigger and heavier bullets because you weren't going to push the velocity up past the limit. This led to some real monsters that were made for hunting in Africa. Bore diameters could exceed 1" and the recoil/blast sometimes caused the shooter to bleed from the ears.
Since most blackpowder "replica" style guns are shot with iron sights, a longer sight radius is very desirable. Also, it's worthwhile to remember that during the timeframe that the original guns being replicated were made, it was not so simple or common to measure velocity. It's entirely possible that they thought the longer barrels were giving them a velocity benefit even though past a point the longer length didn't offer much, if any, benefit....I am curious as to why Remington even made these guns at the barrel lengths they'd chosen!!