The AAC Integrally Suppressed Remington 700 is an American sniper rifle manufactured by Remington Arms. It is a modification of the R700 that has an integrally suppressed barrel. It appears in Battlefield Hardline as the .300 Knockout, where it fires the .300 Blackout round.
— In-game description
It is distinct from the Professional's other rifles in that it is integrally suppressed, meaning it has a permanently attached Suppressor. This gears it more towards close and medium range engagements, as the suppressor causes a large amount of drop compared to the other rifles. However, it still has very high damage, allowing it to still perform effectively at long range if the player accounts for bullet drop.
In January of 2016, the .300 Knockout was nerfed. But it was different on Consoles and PC. On Console, the bolt action was nerfed. So now, you have to wait almost 2 seconds to rechamber the bullet. On PC, the Knockout, and all other sniper rifles were all nerfed so now, you can't get 1 shot kills or 1 shot headshots. Even with the .338 Magnum Rounds on the AWM and R700 LTR