I don't understand the obsession with the Grau. Seems like 8 out of every 10 players I see are running the Grau with iron sights. I jumped into Shipment this weekend just to unlock it and level it up a bit and I still prefer the M4.
I find it much easier to manage overall for me, especially eliminating a large amount of recoil with certain attachments for Warzone. I run it using the longest barrel, mono suppressor, 60 round mag, a holo sight and ranger foregrip. Even without an optic the iron sights I've found to be among the best, so I can swap it for SOH. It's close though, I've recently switched to a heavy variant of the M4 and it absolutely shreds in close. M4 with the 10 round Socom rounds, mono suppressor, grenadier barrel, ranger foregrip and a holo sight, and I'm absolutely loving. I offset the short mag capacity with a p90 as a secondary for that specific class, as I usually run an RPG but can't get caught out with a short clip and having to wait forever for the weapon switch.
The socom rounds are incredible in close and at chunking damage at longer ranges, especially in trios and squads. Would highly reccomend for those looking for a new class or to change things up with the M4 to give it a shot.