If you suspect damage to one of your cases, you immediately take possession of the case and segregate yourself - you take it, locked/secured, directly to their baggage office (if it's not there already), and tell them you suspect damage to your case and contents, and inform them that you want to inspect it right then, in front of them.
Proceed with contents inspection. Anything noted, happens right there in front of them, and they take notes. Have them write a report/statement right there, right then.
I'm no expert at this guys, and I'm not offering legal advice. I have, however, transported and shipped alot of weapons in a past life, routinely, both militarily and as a civilian. MIlitarily, transporting weapons on a commercial air carrier - that can be fun. Under NO circumstances do you ever let a civilian have sole contact with your full auto rifles and any machineguns (M249, M240, etc.). I've had some close calls with airport security (armed escorts) that start off thinking differently. They might be law enforcement, and don't think they're civilians, but they're damn sure not military and allowed unadultered access to automatic rifles... Couple close calls at Sea-Tac a few times, when they either didn't understand or didn't agree with that... <lmao>