Every situation is different so I am just speaking generally here... my wife has been teaching kids between k-3rd grade for nearly 20 years now, and the vast majority of the kids that have had behavioral issues to the point they pop up in our nightly conversations come from split homes where they're exposed to things they're just not ready for (e.g., watching violent movies or even porn, parents fighting all of the time, unsupervised computer use/gaming, drug/alcohol addiction in the home, etc). What you described is on the light side of that scale and your son could be as close to perfect as a kid can be, but he could also be affected by the movies he watches and the words he hears since his mind just isn't ready to process those things. It's awesome you guys are so close, but I am willing to bet he'd be every bit as interested in watching or doing anything with you he knows you enjoy and is more "kid appropriate."
As far as the gun knowledge goes I actually think that's great as long as he's not already taking his own AR-15 out into the backyard unsupervised to shoot birds with ss109 and a 30 round magazine. Being educated about guns and gun safety/handling at a young age is a good thing and it sounds like he's a bit of a prodigy, but being desensitized to what guns can do to people with high tech rated R graphics when his brain is not yet able to process that fiction from reality may not be the best way to further his development. I'll stop there in hopes of not coming off as too judgmental... I know everyone on this forum wishes you and your son nothing but the best.