Attachments have changed greatly in Season 13 and need to be manually redone on the site. This will take quite some time, so apologies if this section isn't helpful right now.
Attachment Details
MX9 - Infantry Compensator
Muzzle
Added in version 1.0.26.0 1.0.26.20
Significantly suppresses vertical recoil at the cost of lateral recoil control.