Been a long time since CanPost or anyone trashed one of my packages, but iirc it's the receivers responsibility to file the claim.
Either way, it depends on what the damage is. If it's blatantly obvious the barrel is bent then it's not to hard to get a quote for a new barrel + installation. If it's a 1911 that's been squished hard enough to effect the slide to frame play then that's more complicated. Maybe the slide can be spread, or maybe it's trashed.
Post the pics, it'll help alot.