My main concern with barring sales until the background check is complete is that it will create a way for the federal government to bar sales. Why does it take more than 3 business days to tell someone yes or no as to whether or not there is a criminal history? If instead of placing more burdens on law-abiding citizens the FBI were ordered to improve their response time then I would be much more interested in that approach.

As for the private sales I agree that the loophole should be closed. I would like to see some more creative approaches than currently stand though. When you look at how you would verify that there was a background check made for the transfer of a fire arm you have to know who owns what gun, and when that changed. That's not something I'm okay with. Gun registration is the first step in gun collection. That's a biased article from the NRA, but the Huffington post argument against it was just as bad. You'll have to ignore most of the nonsense and get down to the meat which is:

"New York City has experience in this arena. In the mid-1960s, street crime was rising rapidly there as in most of the rest of the nation. The people who were perpetrating muggings in Central Park and robbing liquor stores in Queens were not the decent, law-abiding gun owners of New York City. Nevertheless, the New York City Council and anti-gun Mayor John Lindsay enacted long gun registration. The per-gun fee was just a few dollars. The politicians promised that gun registration could help solve crimes and, even if it didn’t, registration was harmless. After all, it was just registering guns, not confiscating them.

As registration did nothing to solve crime or stop criminal use of guns, crime continued to get worse in the city. So in 1991, with the city becoming increasingly unlivable, Mayor David Dinkins attempted to make himself think he was tough on crime, this time by pressuring the City Council to enact a ban on so-called “assault weapons” (such as the M1 carbine).

After that, the New York state police used registration lists to conduct home inspections of every individual whose registered gun had been outlawed. The police were ensuring that the registered guns had been moved out of the city or already surrendered to the government.

Gun confiscation is much easier if guns have first been registered. Pete Shields, past president of the Brady Campaign, explained in 1977, “The first problem is to slow down the number of handguns being produced and sold in this country. The second problem is to get handguns registered. The final problem is to make possession of all handguns and all handgun ammunition—except for the military, police, licensed security guards, licensed sporting clubs and licensed gun collectors—totally illegal.” (Richard Harris, A Reporter at Large: Handguns, The New Yorker, July 26, 1976, p. 58.) (At the time, Shields’ group was called the National Council to Control Handguns. It later changed its name to Handgun Control, Inc., then later changed it again to the Brady Campaign.)

Shields was right to identify registration as a first step toward confiscation. In Great Britain, registration lists were used for the confiscation of every handgun and every semi-automatic long gun."

I want to prevent crime but I am not convinced that it is best handled in the ways presented.