I've travelled with guns (AR + handgun) on Alaska Air no problem (they move quite a few hunters in Pacific Northwest area).
Just make sure it's unloaded, and the case is lockable. In fact, if you can ship your AR180 in broken-down form, that's even better: it's easier to surreptitiously demo to the airline agent that it's indeed unloaded. When you first talk to the agent after standing in line, do
mention right off the bat that you need to declare (a) legal, unloaded firearm(s), and ask if there's a more private area for inspection (like below the counter, behind a lectern, etc.)
If it's a female gate agent, I can assure you she'll be quite wide-eyed.
If they don't know the laws/rules, don't fight with the gate agent. Ask for her supervisor(s).
Eventually you'll get thru. May help to have a printout of the airline's policies on weapons shipping - these are usu somewhere on their websites.
Plan on coming to the airport EARLY since you're "troublesome" and may have to jump thru a hoop. Last time I did this, I got to airport 1hr early. Given the current antiterrorist BS at airports (still wide-open to clever Arabs)
and extra delays already there, you may wanna add even more time as a safety margin.
On arrival, deplane quickly and get to that luggage carousel area ASAP: don't hug the relatives, pee, get coffee, buy a paper, etc. All that can wait: you don't wanna be a victim of an early luggage unloading and have your guns circulating on the conveyor for 5-10 minutes before you get there.
Your request for your luggage item(s) to be held for personal claim at your destination may well be overlooked, and you don't want some Colombian luggage thief to walk off with it.
If on a multi-leg flight, make sure you travel with your luggage. If your luggage is held up, hold up your travel plan. If there is a tight connection and/or flight cancellation due to weather, there's a chance your luggage could go a different route than you do, and in fact end up on a carousel unattended.
Mention these worries to the gate agent at your midflight point(s): when you mention 'firearms' they'll jump thru hoops to keep you & your toys together. [When we had to change flights at last minute in Portland (PDX) on quite a tight schedule, they physically (after I notified 'em about firearms) sent a luggage agent out to collect our luggage and move it to the new flight, and reported the exact physical description to us. And then they upgraded us to 1st class in all of the hullaballooo..
I believe (legally) carrying firearms on planes may allow you to get some added protection/ tracking of your luggage. So when I travel on personal time from now on I'm gonna take my beater AR + a handgun, just for giggles. [Since I'm in the stinking state of Kalifornia, I do carry a copy of my AW reg paperwork just in case there are questions about legal ownership of my AW.]
Travelling tip: you can find .223 ammo about anywhere, not really worth flying with. (You can travel with ammo as long as it's boxed. Not sure if it must be in a different container or not. May help when your rifle is broken down.)
But stuff your buttstock with usu goodies: cleaning rod, brushes, jag, patches, CLP, and a few spare parts.
Have fun!
Bill Wiese
San Mateo, CA