Swampman, Graybeard, and Old Griz are right. If the 30-30 were no good for deer, then why have untold millions been killed via the use of this caliber--either with 150 or 170 gr bullets, 165's in the old days, and even cast bullets? For a lot of woods hunters (and I mean hunters--not shortmag addicts or Guns & Ammo readers) it's still their first choice. While there's nothing wrong with a 30-06, 270, 308, etc, there's also, at least in my mind, nothing like a day-long hunt, alone and on foot, in November, carrying your 30-30 levergun, stopping every now and then to sit along a runway to watch and wait. Somehow carrying much of anything besides a Winchester or Marlin levergun on a day like that, rain or shine, just doesn't feel the same. That time spent is somehow, at least to me, more enjoyable when carrying a levergun. Should you get a shot at your buck, a well-placed 30-30 slug will do the job now, like it has been doing since 1895.
Try spending some time at the range in the spring, summer, and early fall with your 30-30. You might even try it with cast bullets. It's no real trick, if you've shot your 30-30 enough, to bust clay pigeon fragments solidly at 100-125 yds once you're familiar with your 30-30. A little of that kind of shooting should solve any shot placement problems.