i read some sales figures a few weeks back which confirm the stats i read in an article (a survey of folks who hunt) in either field and stream or outdoor life maybe a year ago.

number one rifle - remington model 700 (by a very large margin)
number one caliber - 30-06 (by an even larger margin)
most popular scope (read as best selling) - 3x9x40
caliber is .30 obviously
load - which ever shoots best in that rifle - i suspect most folks just get a box of either corelokts or power points from their local sporting goods store.