Media Matters incompetently discusses a posting of mine
Since the substance of this is the same as a piece that I recently wrote for Fox News, I will just discuss it briefly here:
-- "Virtually no criminal guns are obtained from gun shows." The BJS report "Firearms Use by Offenders" provides a survey of criminals convicted of gun offenses and it shows that 0.7 percent of criminals obtained their guns from gun shows. If one adds in flea markets it still leaves the probability below 2 percent.
-- "Background checks do not stop criminals from getting guns." These guys at Media Matters are pretty dense because they seem to believe that these initial denials are stops that involve criminals when in fact they are almost all false positives. About 99.9 percent of those purchases initially flagged as being illegal under the law were later determined to be misidentified. Take the numbers for 2008 (http://www.ncjrs.gov/pdffiles1/bjs/231052.pdf), the latest year for which data are available. The 78,906 initial denials resulted in only 147 cases involving banned individuals trying to purchase guns. This is before the stage where prosecutors look at the case to see if there is enough evidence to bring a case. Of those 147 cases, prosecutors thought the evidence was strong enough to proceed on only 105, and they won convictions in just 43. But few of these 43 cases stopped career criminals or those who posed real threats. The typical case was someone who had misdemeanor convictions for an offense he didn't realize prevented him from buying a gun.
-- As to delays, 8 percent of the background checks are delayed. Five percentage points of those checks take up to 3 business days, and 3 percentage points take even longer, though these further delays can't stop one from obtaining a gun at that point. http://www.fbi.gov/about-us/cjis/nics/reports/2008-operations-report/ops_report2008.pdf (p. 11) I am traveling and I don't have the reference for the 5 and 3 percent numbers handy.
UPDATE on this discussion and a response to further Media Matters attacks is available here. For some reason I doubt that they will be responding to that post.