A few years ago my brother expressed an interest in getting one of the 30TK's and asked my opinion. I told him I had shot them before and in my opinion they balanced poorly for offhand shooting and swung poorly for shots at running game because they were too muzzle light. The full length magazine tube models are superior for those uses because they add weight toward the muzzle, especially when the magazine is full. I haven't changed that opinion and would pick a model with full length tube every time for that reason. I suspect one of the 24" barrel half magazine models would be better in that regard as the additional barrel length should add enough weight forward to compensate for the short magzine.
The Marlin 336 SC ( sporter carbine) models with the 2/3 magazine have a larger diameter barrel profile than the standard 336c or 336cs models. I find the Marlin sporter carbine models front heavy and personally don't care for them but if your desire more weight up front with the 2/3 magazine the "Sporter Carbine" is your gun.
The Marlin 30TK ( made for Kmart) came with 18 1/2 barrels which will have more muzzle blast. The Glenfield series by Marlin made in the 60's had 20 inch barrels and were offered with the 2/3 magazines.
You would have an easier time finding a Glenfield series Marlin than the 30TK model.
Many Marlin owners of rifles with the 2/3 magazines claim the shorter magazine rifles shoot better and my experience with the 2/3 magazine Marlin rifles bears that out.
