Can’t hit shit? Don’t like shotguns?
Use the M870. “But I just said, no shotguns!”
Shut it, greenhorn!
You’re not going to use the M870 because it’s a shotgun. You’re going to use it because it’s going to teach you how to hit with every other gun.
Why? Because with that shotgun, you’re going to be able to fire 2 really powerful shots when you first see an enemy. Putting the first shot into the enemy, and then controlling that second shot to also be on the enemy, is the same exact mechanism of mouse control you need to use to fire two controlled bursts from Carbines, Assault Rifles, and single shots with the DMRs.
Since Snipers are society’s waste products, we can dispense with those rifles for the moment. Besides, you said you want to really play, not play peek-and-poke on some godforsaken hilltop.
Also, I don’t know where you’re coming from so this might seem obvious, but in Battlefield, with every gun, there’s virtually no reason to NOT zoom when firing.
Only at point-blank range when you’re literally doing a jump-dance in circles around the enemy should you spray.
At all other times, you zoom, you fire one controlled burst, and then repeat with a second. If neither you nor your enemy is dead after that, unzoom and run somewhere with cover to reassess & reengage.
Aiming for the head is preferrable (BF4 is particularly brutal about headshots, moreso than BF3 was), because even a single SMG 9mm bullet clipping the head of some asshole you can barely see at 80m can net you a kill you didn’t expect or, frankly, deserve to get. But even if you can’t shoot the head, big bulky middle is fine.
Because it’s great practice AND great fun, and you’re on PC, I recommend spending some time on a Metro 24/7 server. “But Metro is a clusterfuck!”, you say. Yea, it is, and that’s why it’s the only level of Battlefield that people 24/7. (Well, I’ve seen a Shanghai, but there’s no accounting for taste.) It’s predictable (RU: two flags, US: one, fight up/down the stairs around the station). Ranges vary, good place to get that M870 practice.
Wear earphones, turn your sound up, and enjoy the urban combat that makes Call of Duty look like the teenage pissing match it is.
And now the TL;DR: Use the ACR as Engy, F2000 as Assault. They’re both great at zoomed firing AND passable in point-blank spraying (particularly the F2000). They were both better in BF3, but they’re still great here.
In BF3 the most balanced/flexible loadout in the game was Engineer with ACR with a 6x scope (and SMAW): any target, any range. I can’t done large-scoped ACR in BF4 yet…but it works with the F2000!