"Factory ammo for the .243 doesn't have enough punch for deer"?
My experience with the "puny" .243 has been quite the opposite. And, not only myself, but my mother and my brother both consider my little .243 the best "one-shot-killer" in the gunsafe when it comes to deer and pronghorn. All of my shots on Whitetails and Muleys have been through the shoulders, with a couple of oblique shots smashing a shoulder, penetrating the entire body cavity, and lodging in the opposite hindquarter. Sure, it takes a toll on the bullet (or what's left of it), but I've NEVER needed a follow up shot to dispatch a deer or pronghorn hit with a .243.
Here's where I find people having trouble with the .243 on deer-sized game:
1. Using OTHER THAN 100 gr bullets (I've never had a 100 gr factory .243 fail - Core-Lokts, PowerPoints, and Hi-Shoks)
2. Poor marksmanship
The .243 has done fine by me on deer-sized game. I wouldn't disagree that, depending on where you live and what you hunt, a 7mm-08 isn't a good choice, or for that matter a .308 (if you hunt elk and deer REGULARLY and can afford or want only one rifle).