First of all, the "Brady Bill" had nothing to do with the 1994 Feinstein law (the "assault weapon" bait-and-switch). The Brady Bill was a mandatory waiting period and optional background check, on handguns only, that was passed in the early '90s well prior to the Feinstein law.
The 1994 Feinstein law didn't ban any guns, just marketing under any of 19 names, and far more AR-15 type rifles and civilian AK's were sold in 1994 and after than in the previous several decades combined.
Taking H.R.1022 as the operative definition, more Americans lawfully own "assault weapons" than are licensed to hunt in this country, yet less than 3% of murders in this country involve ANY type of rifle ("assault weapon" or not). Twice as many people are murdered annually using shoes and bare hands as using all styles of rifles combined. And the rifle crime rate is no higher now than it was ten years ago.
The homicide rate did indeed decline in the '90s, due to demographic shifts, rising incomes and job opportunities, and the implementation of "community policing" strategies in lieu of older, more distant/authoritarian approaches.
Please point your friend to this thread:
www.tribtalk.com/showthread.php?t=16466
Rifles, even small-caliber ones with modern styling, are not a crime problem in the United States and never have been.
FWIW, only 1 in 5 U.S. gun owners hunts. 80% of us are nonhunters, and we'd like to keep OUR guns too. The AR-15 platform is the most popular centerfire target rifle in the United States, and is also the #1 defensive carbine; the ammunition it uses (.223 Remington) is the #1 selling caliber of rifle caliber in the nation.
He is certainly free not to own one, but a lot more of us own "assault weapons" than own .270's.