Minium caliber considerations?

[Mr. 16 gauge]

I know that various states have minimums, which may or may not be based on any data or practical knowledge, and now that in-lines are the prefered method for "primative" seasons, the waters are muddied even more.....


......so, based on YOUR experiences, what do you consider to be the minimum caliber for the taking of white tailed deer (and similar sized game) with a traditional style rifle? Assume that we are talking BP (no substitutes) and patched round ball only (no conicals), and maximum range of 100-120 yards or so.

Thanks in advance for your opinions............