I hear this one a lot. "The military is so big, they have missiles, drones, etc etc etc, you could never defeat them in battle." This argument has several flaws:
1. This is just more proof that we (the people) need to hold on to whatever arms we can get. We've mistakenly let our military accrue a cache and kind of weaponry that we have not allowed even ourselves to possess. If the powder keg does explode, less arms is not better than more.
2. Many service men and women take their pledge to uphold the constitution very seriously, and would not take up arms against the American people (and most likely would take up arms against a tyrannical government, should it come to that). This is why many veterans are proclaimed mentally incompetent and disarmed (http://www.benefits.va.gov/pensionandfiduciary/fiduciary/ben..., http://www.youtube.com/watch?v=5NlBgtIeU1s).
3. There are 1.5 million active military personnel and 850 thousand reserves (Wikipedia). There 311 million Americans, not including the roughly 3 million that are active or reserve military personnel. We are a bigger force by far.
4. "You're going to die if you fight." Appeal to emotion.
5. "How can you even say that with a straight face." Appeal to ridicule.
6. There are many reasons to "want a gun" beyond protecting yourself from tyranny, including self defense from criminals, sport, hunting and recreation. But "wanting" has nothing to do with it. You don't need to explain why you want a gun and you don't have to show a "need" for it. It is your inalienable (seriously, look this word up, ponder its meaning) right. It cannot be taken from you (though you can give it up willingly, I suppose).
EDIT:
7. In 2011, Ron Paul received 6 times (http://ronpaulronpaul.com/) more in contributions from active military personnel than all of the other republican candidates combined. For those that don't know, Ron Paul ran on a campaign of small government, less war, etc. That should tell you where our military stands on this matter.