Sir,
If you are flying with those weapons, I sincerely/strongly suggest that you use foam in the case (preferably custom foam).
Do you have optics mounted on the carbine? If yes, then do not go the soft case inside the hard case route.
Why?
I work at a major airport and I have seen first hand what happens to luggage once it disappears into the bowels
of the terminal. It is not a pretty thing to watch.
There is the lore of gorilla-like baggage handlers, but, the most consistent culprit of bag damage is the
automated bag handling systems that most airports use. There are battering rams that slap the bags from one conveyor
to the next.
Then, there are the baggage trains (carts pulled by buggies...you see em' running around all over). I have personally seen bags fall off
these trains. At night, bags fall off and get hit/run-over by vehicles.
Lastly, the bags occasionally fall off the conveyor when being loaded/unloaded from the aircraft.
The last thing you need is to open your case down in TX and find a damaged optic/rifle.
Invest in a good case with foam. You'll sit back on the airplane, sipping your favorite beverage, thinking about training at CSAT and not worrying about whether or not your weapons will show up undamaged.
Sure, a case with foam is not cheap, but, it is a one-time investment that pays for itself over the years that you own and travel with firearms.