I use a 4x28mm on my 336 when I feel like using a scope, most of the time i just use open sights but in some cases a scope is very helpful ( eyes arent as good as they used to be). that size of scope has a perfect feel sitting on top of a marlin 336 plenty of magnifacation for what you will be doing with a 30-30 and doesnt add much weight to the gun either. I also use the same kind and size of scope on my remington Mountain rifle in 308 win. hope this helps