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
MIP Light Barrel (Short)
Barrel
Added in version 1.0.15.0 1.0.15.17
Increases movement speed and flexibility at the cost of accuracy and range. Suitable for combat in a cramped space.