You're putting bicycle wheels on a truck, if that metaphor makes sense.

"Political power grows out of the barrel of a gun" is not the same as "might makes right" although they can be seen as similar.

Might makes right is the justification of victory, of opposition or the lack there of. It's the language of colonizers, that if someone was a victim, they should have just been strong enough to resist. That, by virtue of victory, the victor is correct. It's a cyclical argument, the law of the jungle.

"Political power grows out of the barrel of a gun" is less about what makes something right or wrong, and more simply about the facts. Communists aren't right because they defeat capitalism through revolutionary violence, but revolutionary violence is still necessary.