As I understand it, most pistol cartridges do not really benefit much from the longer carbine barrel compared to a full-size (5") pistol barrel. One of the exceptions to this rule is the .357 magnum; velocities are significantly higher from a carbine than from a revolver.
I owned a Marlin Camp 9 for a while. It was a nice little gun, but I decided that I'd rather just have a .22 for plinking/range use.
Slightly true with fast commercial ammo but not the case with handloads.
I have got 124gr 9mm bullet to 1650fps using blue dot and a 90gr bullet to 2090fps...
Can anyone explain to me why a .357 mag gains considerable FPS but not .357 sig?
I also know that the .357 sig is bottlenecked but do you know of a handgun caliber that shoots flatter and faster besides 5.7 and tokarev?
Seems to me that its at least a untouched market.. whether it could be profitable.. who knows