For plinking, right out of the box the Marlin 94 will feed both 38 and 357. However you state your purpose for the gun is predominantly CAS so the .38's need a little tweaking to feed smoothly every time...no double clutching or hesitations allowed. A few years ago I did an extensive test on .38 OAL that would feed the same every time...no exceptions. The length I found that will work is 1.515. To seat at this length the crimp (and I crimp very firmly) will be between the crimp groove and the first grease groove an any of the common hard cast bullets out there (125-158 gr). There is no noticeable accuracy reduction that I can see from doing this and I've loaded 10's of thousands that way since the testing was done.
The initial testing was done with the wife's first Marlin 94 but I have subsequently tested them in every Marlin I could get my hands on ( at least a couple dozen or more so far) and have not found one that won't eat the 1.515 length .38's like candy.
Just a comment if I may as someone mentioned the Rossi's/92's. I have 3 or 4 of them myself and they are great...for plinking and rudimentary "non-serious" CAS shooting... but if you want to be competitive in the CAS game there are really only two actions I would recommend you wait until you find one, either used or new, those being the Marlin 94 or the 73 Winchester clones (Miroku or Italian, it matters not which).
