25-06 is a good caliber for deer and varmits. not sure about the marlin rifle. mine was a Remington 700 and it is still killing deer. sold it to my brother for one of his boys. he still thanks me for that rifle. loaded down with 75 or 85 grain bullets will do a number on groundhogs. 117 grain bullets will do the same on deer. nosler partitions would be a good bullet for deer also although I never used them.