I've checked and there seems to be no such animal as the 'switch rate barrel' you claim a Marlin has. If you are implying that the Marlin's barrel has the ability to change the spin rate of the bullet, then you are claiming something outside the laws of physics. In a perfect condition, the bullet's rotation in all rifled barrels is dictated by the rifling which is fixed, i.e. 1:20 (which means 1 revolution per every 20" traveled) no matter how fast the bullet is traveling.Your Marlin has a 20" switch rate barrel, and that makes a big difference!
When you shoot a .310gr bullet (I use the Lee mold), the bullet is slower, so: slower speed, and slow rotation speed, that don't give good results at long distance!
I think that the Rossi 24" is really good for fun shooting, pin shooting, CAS, deer hunting at short range, but if you want to shoot at 100m or longer, it is better to choose for instance a Marlin, an Armi Sport(http://www.armisport.com/eng/menuAS.asp), or a Contender......
Personnaly, with it I make a lot of target shooting at 50m, gong shooting at 25m, and maybe one day roe deer hunting.