I was making these short vids on the fly as you can tell by the phone quality. the barrel goes in the same as the vet 1 except the wrench slot is at the muzzle end whereas the vet 1 has it at the breach end. you do NOT need to remove those 4 screws or the shroud to remove the barrel. But the flange for the mod does need to come off so you can get a skinny wrench onto the barrel groove.