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?   Sig Sauer M400 semiautomatic assault rifle The Sig Sauer M400 semiautomatic assault rifle is advertised on Walmart’s website as “designed for use in law enforcement, military operations…as well as competitive shooting.”   “Imagine my shock to see this rifle hanging in the gun case at my local store,” a Utah reviewer raved on the Walmart site. “I went back the next day to get it, alas, it was gone. No biggie, there’s always another Walmart within a couple dozen miles right? Two hours later I had one in hand.”   Semiautomatic Colt M4 OPS .22 rifle Colt’s M4 Ops .22 rifle carries a thirty-round magazine, which you can also purchase at Walmart.   Colt LE6920 Carbine Semi-Auto Rifle, 223 Rem/5.56 NATO This Colt semiautomatic rifle comes with high praise from one Walmart reviewer: “I am a former Marine and this is just the same as the M16 but for the AUTO, never used AUTO that much in the Marines anyway.” That’s reassuring.   Smith & Wesson 811030 MP1522 Rifle and Remington 870 Express Tactical shotgun When James Holmes killed twelve people and injured fifty-eight others in an Aurora, Colorado movie theater, he was carrying a Smith & Wesson M&P15 (another in the AR-15 class of weapons) and a Remington 870 Express Tactical shotgun, along with two handguns.   Winchester 22LR Hollow Point Rounds, 555pk There are also 381 types of ammunition listed on the Walmart web site. You can buy a 555-pack of Winchester hollow-point bullets, which the Walmart website advertises as “great for plinking and varmints,” but which would cause extensive damage should they enter a human body and expand, as they are designed to do.   How are local activists pushing back against the biggest seller of firearms and ammunition in America? Read George Zornick’s article, How Walmart Helped Make Newtown Shooter’s AR-15 the Most Popular Assault Weapon in America, ;to learn more.