Firstly, my upmost respect for anyone who serves their country. What I'm about to say is basically a rebuking of some of the finer points you've said, but I do really respect that you're trying to educate the misinformed, so I hope people won't view this as a "omg ur wrung dun be wrung" post, but rather, as a more in-depth view of ballistics as a whole, particularly from a more scientific approach =)
Anyways...
Just a cursory glance, but I think you've made a few major mistakes;
1. Muzzle velocity for all 5,56 rifles is going to be different. For example, the L85A2 has a muzzle velocity of 940 m/s while the Ak101 has a muzzle velocity of 910 m/s. It'll also depend on the quality of the ammo used. Even then, muzzle velocity isn't a good approximation of how much "damage" a bullet is going to do when it impacts. You have to take into account the bullets deceleration (a heavier bullet carries more of a punch closer up, but a lighter one won't slow down as much at longer ranges) and the "payload" of the projectile as well. (Hollow-point, FMJ, Armour Piecing, subsonic, etc.)
2. Accuracy primarily depends on the internal mechanism, not the barrel length. Accuracy is itself kind of a weasel term. In any firearm, what you'll really want to look at for "accuracy" is flatness and grouping. Flatness is, in laymens terms, how flat the trajectory of the bullet is (and primarily influenced by both weight and muzzle velocity) whereas grouping determines how far apart projectiles shot under the same ideal conditions will possibly be. Ironically enough, these work against each other in barrel length, so a longer barrel will mean better grouping, but less flatness, whereas a shorter barrel can get a flatter bullet, but a worse grouping. (Again, a simplification, as it doesn't take into account rifling or the sweet spot for muzzle velocity, but a valid comparison nonetheless)
3.
4. No mention of the difference between the M4 and M4A1. Never mind SOPMOD.
If you're taking suggestions, I think you should cover the XM8 or L85 series of rifles next. Far too many people seem to view these guns are some kind of "megaawesomesupergunrifles", which simply isn't the case.
Anyways...
Just a cursory glance, but I think you've made a few major mistakes;
1. Muzzle velocity for all 5,56 rifles is going to be different. For example, the L85A2 has a muzzle velocity of 940 m/s while the Ak101 has a muzzle velocity of 910 m/s. It'll also depend on the quality of the ammo used. Even then, muzzle velocity isn't a good approximation of how much "damage" a bullet is going to do when it impacts. You have to take into account the bullets deceleration (a heavier bullet carries more of a punch closer up, but a lighter one won't slow down as much at longer ranges) and the "payload" of the projectile as well. (Hollow-point, FMJ, Armour Piecing, subsonic, etc.)
2. Accuracy primarily depends on the internal mechanism, not the barrel length. Accuracy is itself kind of a weasel term. In any firearm, what you'll really want to look at for "accuracy" is flatness and grouping. Flatness is, in laymens terms, how flat the trajectory of the bullet is (and primarily influenced by both weight and muzzle velocity) whereas grouping determines how far apart projectiles shot under the same ideal conditions will possibly be. Ironically enough, these work against each other in barrel length, so a longer barrel will mean better grouping, but less flatness, whereas a shorter barrel can get a flatter bullet, but a worse grouping. (Again, a simplification, as it doesn't take into account rifling or the sweet spot for muzzle velocity, but a valid comparison nonetheless)
3.
This isn't strictly true. I won't bore everyone with the details. The M2 is more comparable to the M16A3, while the M3 is more comparable to the SAMR. I don't want to go into details now (I will if people insist) but M-designations during WW2 and Korea were different to what they are right now.The M4's predecessor in the carbine family was the M1 Carbine, which had variations known as the M2 and M3, which was in service from World War Two through the Vietnam Conflict.
4. No mention of the difference between the M4 and M4A1. Never mind SOPMOD.
If you're taking suggestions, I think you should cover the XM8 or L85 series of rifles next. Far too many people seem to view these guns are some kind of "megaawesomesupergunrifles", which simply isn't the case.