Many people ask eNotes contributors questions about how to write a thesis sentence or a thesis statement. But it is impossible to give you a helpful answer without knowing what your own thoughts and feelings are about the subject.
In order to come up with a good thesis statement, you should first forget about the statement and write about your personal opinions. Are you in favor of gun control? Or do you oppose gun control? Are you in favor of some limited gun control, such as control of AK47s? What sort of control, if any? Isn't there enough gun control now? What would be the benefits of more gun control? What would be the harmful effects of, say, taking guns away from everybody? What is the problem with guns? How would you cope with the American Rifle Association? Who would enact the gun control, if you favor it?
After you have done some thinking about your own--your very own--feelings and opinions and reading on this highly controversial subject, then you would be in a better position to form your thesis statement. It should be fairly modest. You can't cure all the world's problems with one short article or essay or term paper.
If you try following my suggestion and then formulate a thesis statement, you would be welcome to submit that statement to eNotes for criticism. I especially recommend that you spend some time writing about your own thoughts, feelings, opinions, etc., before you try to formulate a thesis statement. The thesis statement is the idea you are trying to sell the reader. You have to know what it is you are trying to sell him.