I'm not sure - there's good and bad in the gun debate. For sure, it's not guns that kill but the people wielding the guns but, just as surely, the easy availability of guns must increase the chance of guns being used improperly or accidentally.
However, it's hard to fault the "guns stop tyranny" argument:
...if I were a tyrannical US Government, I'd put Texas a square last on my list of states to take over. It has 25 million people and, quite probably, more than one gun per person. Even if you assume that gun ownership is concentrated, you're still looking at 5 million or more heavily armed and motivated citizens who know well the expansive lands of their state. Contrast this with a total of 1.4m active and 0.8m reserve personnel in the entire US Armed Forces and note that the actual gun-toting soldiery won't be even half of that. Unless you planned on levelling the entire state with high explosive, you'd be nuts to try to take on Texas. Britain, by contrast, should be a walk-over.
It's a fair point.