The straightwall cartridges do gain velocity with longer barrels but it’s rarely 100s of FPS. So shorter barrels don’t hurt performance as bad. So in my *opinion* 20” and shorter lever guns firing straight wall cartridges make sense. You get workable velocities and its handy. A 16” Rossi in .357 is so convenient. It goes in and out of truck cabs so nicely. It could fit in a backpack. It weighs nothing and recoils mildly. The Marlin Guide Guns 18” barrel, a happy medium between the 20” and 16”, I think they balance at the action decently as well. 45-70 out of an 18” is still happily over 2000fps with 300gr bullets and heavier. *Personally* a 16” .308 doesn’t make much sense to me. You lose what I *personally* think is too much velocity to get a “handy” rifle. The tanker M1s were necessary because of confinements and a need to stick to the standard military cartridge of the time for obvious supply issues. As a private citizen with the world at your fingertips I believe a different cartridge could do the same thing better. Now in the other direction. A long barreled lever gun or straight wall cartridge gun makes sense if you say hunt deer in Iowa and are restricted to cartridge and want maximum range. Others might say “ I like the longer lever guns because they’re historical” and sure. But why do you think they were so long? They were restricted to a cartridge of the time and wanted maximum range. . But the beauty of it is. Most of us on this forum live in America and can buy and shoot whatever the hell we want!