I have a old bushnell fixed 4x on my Marlin 30/30. I would suggest going with a brand that has a better reputation than simmons and drop the price back by going to fixed 4x. 30/30 is a fantastic brush gun easily capable of killing a whitetail out to 200yds. 4x works well within those parameters. Nikon, Burris, Leopold, Redfield, Weaver all have value lines that will hold up to a 30/30.
Concentrated power is not rendered harmless by the good intentions of those who create it.