True, our party hasn't fully embraced RKBA so it is still an wedge issue that the Republicans can use against us.
The idea of draconian gun control laws and bans still appeal to the very liberal portion of our party. A push for another assault weapons ban or gun registration or an attempt to impose some of the new concepts such as microstamping ammo will cost the Democratic Party dearly in many close elections.
I believe that we can work to fine tune and improve existing laws. The NICS background check has proven valuable but better funding would enable states to automate their records and update the federal database quicker. Millions of records are missing because of technology and funding issues.
We can also push for strict enforcement of existing laws. All too often, people are caught illegally carrying firearms in public and only receive a slap on the wrist. Imposing a stiff sentence for packing heat would reduce many gang related shootings and make our streets safer. This is just one example where we need make sure the current gun control laws have teeth.
You have to remember that many people have a considerable investment in firearms and enjoy the shooting sports. If you have a collection worth 5 or 10 thousand dollars (or more), you will definitely take the time to vote for a pro-RKBA candidate if you worry that your collection and hobby is endangered. Most people who oppose firearms don't own any and while they would like stronger gun legislation, it isn't as high a priority as stopping draconian gun legislation is to a person who opposes further gun control.
We do need to stop listening to the Brady Campaign or the Violence Policy Center for advise on gun control. Following their suggestions and promoting draconian gun control measures has lead to Democratic candidates shooting themselves in the foot many times.
A quick look at this "Right to Carry" map should lead any rational person to understand that harsh gun control is a losing issue. If the majority of people were in favor of further harsh gun control laws, they would definitely would have shown up at the polls to stop laws that allow people to carry firearms in public.
You could argue that gun control is such an important issue that it takes priority over all other issues and that losing elections isn't as important as sticking to important principles. Most Democrats would disagree with you. Our party won the Presidency and control of Congress at an unfortunate time and we are faced with
many important issues. Harsh gun control doesn't rank that high.