Within 20 minutes of paying $8 to enter Bill Goodman’s Gun and Knife show at the Vandalia Aiport Expo Center earlier this month, I was offered an SKS semi-automatic rifle with a 30-round magazine for $450, no background check required.

The seller, who didn’t give his name, said he had the gun for years but was selling it because the price of semi-automatic rifles had ballooned.

Another man, who gave his name as John, strolled the aisles of the gun show with a semi-automatic Ruger Mini-14 slung over his shoulder. Taped to the end of the barrel was a piece of paper listing four guns he had for sale.

They included an AR-15, commonly called an “assault weapon” or “military style” gun because it looks similar to weapons used by SWAT teams or military. This is the same type of gun used by shooter Adam Lanza at Sandy Hook Elementary School.

John said the AR-15 was available for $1,500, “straight out of the box.” I asked to see the gun and was escorted to John’s car in the parking lot and shown the gun in the trunk. John offered to throw in a second 30-round magazine with a cash purchase.

When asked if any paperwork was required, John said no. He said I only needed to be an Ohio resident and be allowed to buy a weapon. I told John that I wasn’t a felon.

There would have been nothing illegal, or even uncommon, about the purchase. Guns constantly change hands among private parties in Ohio with no background check required as long as the seller isn’t a licensed dealer. It’s often called the “gun show loophole,” but it also applies to guns sold at flea markets, garage sales and among friends.

Back inside the gun show, semi-automatic rifles of the type some are calling to ban as “assault weapons” were plentiful, along with semi-automatic pistols, shotguns and uzis, bullet-making kits and myriad survivalist gear.

I asked a couple dealers about background checks, and was told they were absolutely mandatory and could take minutes or days.

AR-15s sold for about $1,450. Some collectors said not long ago they could be found for less than $800.

Demand was high, dealers said, with people buying up semi-automatic rifles for fear they would be banned. Some were skeptical that any gun control legislation would be passed, and felt it best to let the buying spree pass and buy when prices drop.

Frenetic sales have led to an ammo shortage, driving the .223 ammo used in most AR-15s to about $1 a round. Many stores – including Dick’s Sporting Goods locally – couldn’t even estimate when they would have it in stock.

So for anyone who did acquire an AR-15 and a 30-round magazine, the trick, some dealers said, would be finding ammo to fill it.