I call BS. McCain doesn't have anything. Look at his stance on illegal immigration.
Back to the main subject, the most common crime guns are (if I remember correctly) split between two general groups:
-about 4 or 5 types of really cheap, really crappy guns in small calibers that were probably made in 5 minutes each with a sheet metal stamper. Names like bryco, jennings, etc come to mind. Even if the gun didnt explode halfway through the first mag, the bullets are so weak it wouldnt matter.
-high quality guns that were obviously surplus police firearms such as 38 caliber S&W revolvers and 9mm Glocks. In a few years we should start to see the used 40 S&W Glocks showing up in crime statistics as today's cops start to replace their old guns.
No gun banner has ever suggested either:
-a way to stop criminals from setting up gun factories in warehouses and cranking out cheap disposable pistols (it isnt possible anymore than permanently stopping weed or meth or booze is)
-stopping police from selling their used pistols onto the secondary market every couple of years (it isnt politically popular to stop the police gravy train. However, it is funny when NJ politicians try to sue Glock because a pistol they sold to NJ police was resold to a pawn shop and then to a criminal. Then again, NJ police are a criminally suspect class, so Glock was clearly negligent in selling them pistols).