I appreciate hearing from you on this. From what I understand, it's pretty common for little boys in military households to refer to their penis as their gun as a more "polite" term. And since the chant goes, "This is my rifle, this is my gun..." perhaps it is reinforcing the use of correct terminology, if you are saying that gun = penis and is distinct from rifle. But it's still a conflation of violence and sex.
How can rape not be the norm when 1 in 6 women experience it, and 1 in 3 experience some other kind of sexual violence? The rape of men by other men takes place most often in prison and in the military. 38 men are raped every day in the military - a place where violent domination and sex are clearly conflated (as also demonstrated by the astronomical number of rapes of women in the military as well). At least 25% of women serving in the U.S. military have been sexually assaulted, and up to 80% have been sexually harassed. A 2011 report found that women in the U.S. military were more likely to be raped by fellow soldiers than they were to be killed in combat.
About 25% of college guys admit to sexual coercion, but that means that the number is much higher society-wide, so although most men are not rapists, it's also not a small number who are and maintaining power and control through sexual aggression is still a very baked in part of both the military and the larger society.