Weapons across Call of Duty: Black Ops 4’s different modes share mostly the same statistics except for one big thing: weapons in Blackout have not received the same updates from patches that they have in other multiplayer modes.
Several weapons have gotten nerfed or changed in some way since the release of Black Ops 4, which came out on October 12, 2018.
But it looks like those changes didn’t affect any of the weapons in Blackout mode, which apparently has gotten it's own weapon updates and patches.
According to a YouTube video by Call of Duty expert TheXclusiveAce, most weapon stats are the same between Blackout and other multiplayer modes, except in certain cases like the ICR-7.
The ICR-7 received a nerf that drastically reduced the effectiveness of headshots, but not in Blackout, where the weapons stats remain unchanged.
This means that the ICR-7 is much more powerful in Blackout, provided players are actually able to hit those headshots.
Other weapons, like the Spitfire and Auger DMR received recoil nerfs in Blackout that they didn’t in other Multiplayer modes.
Based on this, it looks like Treyarch might intend to keep weapons just slightly different between Blackout and other modes.
Because of this, Black Ops 4 players will have to be on the lookout for multiple patch updates to the latest Call of Duty title.