Obama is not going to announce any sweeping gun control changes tomorrow for a couple of reasons.
1) He does not have the support in congress for it. If he tried to suggest or get a bill passed and it gets massively shot down in congress then he loses face and the country sees him as not as not having the power he wants us to believe he has.
2) He will let the states and their legislators take the lead on this. Let those states like NY, IL, and CA be the high water mark for what they can get to fly. Other states can then be pressured to adopt similar statutes. Additionally if the federal government passes sweeping firearms legislation, the states can simply bypass it.....another loss for team Obama.
3) He would never come directly at the gun lobby, even throgh EO. He knows full well he does not have enough of the country supporting this agenda and does not want to encounter both the political backlash and potential civil unrest/disobedience of the general populous. For gun owners to willingly not comply with federal mandate or EO would show in bright neon letters that he does not have the power to take on this nation head on. This weakens his position and places him on very shaky political ground.
What we are likely to see is things that will be much more insidious and back handed.
1) He will tie mental health in with firearms ownership. While this sounds like a great idea, especially when you talk about keeping firearms out of the hands of the "crazies", it has some very unsavory but less talked about repercussions. Mental health evaluations are subjective at best. They are heavily biased on who is administering the test and what they "want" the outcome to be. Here is an example. You end up getting divorced or suffer the losss of a parent, child, close friend, etc... In an effort to deal with the grief, you enlist the help of a mental health professional or doctor. With these new EOs and the mental health industry tied to firearms, they are by law required to notify the sherrif that you have been seeking counseling or mental health assistance. That in turn triggers an immediate search of your premises and seizure of ALL of your firearms. BTW, your CCW permit also gets pulled. Getting your stuff back will require the signoff of a state approved or state employed psychologist. Oops, you failed again...sorry try back in another year. Sorry failed again.. the state now considers you too dangerous to own firearms.
2) Things like online sales of ammunition and weapons are likely to be outlawed. This makes it more difficult and expensive to "feed" your firearm.
3) Taxes on ammunition and firearms to help pay for these programs.
4) A new national background check system. Oh BTW, there will be a $50 per firearm fee, paid to the fed, to perform this check....oh yeah, one more thing, every firearm transfer....every single one now needs to be run through the system.
It is not going to be an outright attack. It will be an erosion of our rights, a little at a time. They move the line a little farther to the left each time. Once we get used to it's position they move it a little farther left. Pretty soon he has essentially nullified the Second Amendment by limiting what firearms the public can have to such an extent that those firearms are not a threat. Once the Second Amendment is gone, the rest will fall as well.
These are all things he can do without ever taking away anyones firearms or outlawing a particular weapon.