Been following this thread for a few days, and it rates up there for entertainment value, but I'd like to add that nobody ever said TB powder wouldn't be enough to kill a deer, but in fact the consensus has been that "there are better choices" and I'm pretty sure this would be agreed to by most serious deer hunters on this forum.
The rainbow effect of the projectile at longer range, and the possibility that deer don't always come out and stand broadside at exactly 100 yards is probably why a serious hunter would want something a little flatter shooting when they take to the woods no matter what you shoot with, and the 45-70 with the right powder will shoot flat out to 200 yards should you need it.
We could argue the point all day, and the bottom line always comes down to this, and I don't think anyone would argue the point, but when you only get to hunt deer but for a few weeks or days of the year, you want as much in your favor as possible within your control in order to be successful.
I've read many threads on this same forum by the same guys posting on this subject that have favorite deer loads and they post them when someone ask for load data (I've taken their advise on several occasions) on the 45-70 for a deer hunting load and TB usually isn't even mentioned, and the reason is just as I described above, and that is because there are better choices.
Don't take this wrong and flame me that I'm knocking TB because I'm not, and in fact I love the powder, but it is made for it's purpose and that is a low velocity, not beat you to death target/steel load for cowboy action shooting.
Personally folks can pack as much powder as they feel safe to pack into a case and shoot it above the published load specs, and that is their choice, but until the day comes that the manufacturer publishes, (not I talked to this or that guy) you can do it without any harmful effects either to accuracy or personal, then I will choose to not to do so, as I will with any powder.