Archery. To the best of my knowledge, a minor can buy a bow and arrows and any restrictions are through store policy. Other States might require a buyer to be at least 18 or have their parents with them. Automatic weapons are still legal here if you have the proper license for it. I'm not sure how much longer that will last.

They are alredy outlawed in california except for existing license holders.

Considering that any automatic weapons made after 1986 are banned for civilian use even with a license, I'll probably have to get a couple through the black market, find someplace remote to practice with them, and stash them away in case they are needed someday due to civil or political unrest. I might be able to still aquire military surplus and second pary manufacurer parts to build a Thompson, AK-47 (available with closed bolt), M-14 (available in Cal. as M-1a), SKS (available with closed bolt) , Browning .30 MG, Browning .50 MG, M-16 (Blah!), or M-60. With the assault rifles, all you have to do is find a competent machinist who has created homemade open bolts and selective fire switches for the particular gun. I even saw one on the internet for a Glock! (I'll have to check out what model again).
