Simply put, I expect few if any seats to pass to legislators sympathetic to gun control in the next election. I think we're good on that for now.
I believe you are correct the legislator is probably not the biggest threat to gun rights. In my opinion the biggest threat to gun rights is the Judicial Brach with the SCOTUS being narrowly divided on Second Amendment issues. I fear the anti-gun crowd is not pushing legislature because they plan to use the court to accomplish what the Congress never will and that is increased firearms restrictions.
The current President may very well end up appointing new Justices before the end of this year. Also the next President, be it the current guy or someone else, will most certainly be appointing new Justices. This seems to fall through the cracks for a lot of folks, but the Supreme Court can do in one day what the legislature could never do. It is very important to assure Jurist are appointed who will protect our freedoms not destroy them.