In the Boston case, I am more worried about the IEDs they used than the firearms. You ever seen the kind of shrapnel injury those things can cause. Plus you can build one using stuff at home deopt.
As for the gun control issue. I guarantee the cops use firearms that hold more than 10 rounds in the magazine. This is because targets tend to run in a zig zag pattern making hitting them much more difficult. The only time a 10 round magazine helps is if the target is running at you in a straight line, like an idiot who has noting else to live for with a bomb strapped to his chest.
At which point, you may also want to create some distance between the suicide bomber and yourself.
Bad guys will find a way. Crazies will find a way. Evil will find a way. This is because they do not follow the law. Last I remember, it is illegal for law abiding citizens to detonate an IED on the American people. But guess what, it still happened because they will find a way.
Removing firearms from law abiding citizens like myself would only help out criminals. Firearms are tools. Evil crazy people are the real problem, but no one wants to admit it.
Much like personal self control is the problem why America is getting more and more obese.