First off, waste an attachment I don't care. That being said why do people think that the armor-piercing attachment increases your damage against other players? IT DOESN'T! That little green bar applied to the damage bar is the extra damage you would do against enemy vehicles. stop thinking it applies more damage against players.
Now to the controversial part, Submachine Guns. I'm not complaining, I'm just sayin. Some will agree and disagree with me and I know guns aren't created equally. I know they just nerfd the bison and cbj but why stop there. Most of the sub-guns are op and ridiculous with the range/damage ratio. what I'm saying is overall most have to much range with the damage they have. yet on top of that you can put a muzzle brake on it increasing the range a good bit. I've seen and have pulled off shots that should be out of a 5-8 bullet kill range when it actually kills you in 5-8 bullets(without muzzle brake) where that you think you would be shooting a AR and be getting hit by a AR. The range on most should be dropped. I'm not a hater on sub-guns I use them, I use everything its just there needs to be more balance. Feel free to respond!
I like how you said until you someone acts dumb, how will you know they are acting dumb, it will just be your opinion won't it? The SMG's were always fine for me, move on and adapt is all I thought. The only gun I saw getting nerfed that didn't need it was the cbj. It was already an undecent gun and people rarely used it. Now that it is nerfed it is basically a peashooter. And like you said armor piercing doesn't increase regular damage but it increases damage to streaks and through walls.
You're right about the ap attachment. I'm not sure why the devs show that damage increase. They've done the same thing with fmj in previous games. Ap still serves a purpose, but isn't nearly as effective as it would be if it added damage.
I think the range on the smg's is fine. The maps in this game are bigger than those in previous games. If smg's didn't have that range, then the game would be dominated by even more ar's and lmg's.
SMG's are not supposed to have the range of an AR or MR, they are "supposed" to be dominate at CQC range, that is the whole purpose of them being SMG's and not PDW's. The MTAR is really the only SMG I have an issue with, it barely has any bullet spread when you use rapid fire and grip at long range and I will get melted by it. You don't even need muzzle break for it to be effective at longer ranges.