my first deer rifle was a 30-30 marlin i used it for 20 years killed more deer than i could keep up with,all died fast.The gun wore out and i changed to a bar 270 and a rem. youth series in 243 cal. I have hunted only a few seasons with the 243 but it has proved to be deadly.Comparing the 30-30 to the 243 at 150 yards i would go with the 243.Although a perfect hit with a good 150 gr. 30-30 bullet will kill most animals at 150 yards.danny