"Minneapolis interim Police Chief Tim Dolan said that 75 percent of the guns recovered on Minneapolis streets are from Minnesota, and he urged Minnesotans to report when a gun is bought, transferred or stolen."

http://www.startribune.com/462/story/441909.html

Just where does he think we should report private transfers? Even if you wanted to do so, there is no such form or proceedure.

If they're stolen, sure, report them.

Does he think they should all be registered, or is this just the opening round of trying to require all transfers to go through an FFL?

Sure there is.

http://www.revisor.leg.state.mn.us/stats/624/7132.html

It's not required, but you can do it, if you really want to.

Even if you fill out the form, it isn't going to make it any easier for a law enforcement agency to do a trace. This is just grandstanding.