When Adam Lanza entered Sandy Hook Elementary School on Friday, inexplicably bent on ending as many lives as possible, he was carrying a Bushmaster AR-15 assault rifle and several high-capacity magazines. Although it is not clear yet where the AR-15 used by Lanza (which was registered to his mother) was purchased, the model is familiar to many shoppers at Walmart. It’s on sale at about 1,700 Walmart stores nationwide (though the retail chain pulled the weapon from its website early this afternoon), along with other guns of questionable use for duck hunting. Which other assault weapons can shoppers pick up at their Walmart?