re: Ammo in your rifle cases: Most of the employees at the airport barely graduated high school. They never see guns and archery gear so they just go off what they heard someone else say and make it up as they go. I fly Delta most of the time and always have this page pulled up on my phone for when they inevitably tell me I can't put ammo in the gun case (wrong). (scroll down to shooting equipment:
https://www.delta.com/us/en/baggage/special-items/sporting-equipment). Whatever I'm flying I always have the rules pulled up on my phone so I can show them at check in before a Shanequa wants to get huffy with me. In 20+ years of flying there was one airline that explicitly said ammo can't go in the locked gun case but I forget who it was. It's always a pain in the ass checking the gun to canada. Coming home its a breeze. They actually know their laws.
re: TSA locks. The last few times I've gone through security they have me open the case and I always say "they're TSA locks, you can do it" and the reponse is either A: "We need you to be present when we open it or B: "They don't give us the TSA Keys anymore". I still use them but it's almost pointless. Once you start flying internationally TSA locks don't matter as it's only good in the USA.
On my most recent trip home from Iceland I was checking a gun next to 30 kids from NATO who were headed to the Ukraine and they were checking AR-10's in duffle bags with no locks and just pulling off the lower and throwing a zip tie on it. I died laughing.