I use a Pelican Storem 3x00 series “dual" rifle case (with regular foam, no cut outs) and have had no issues with TSA. Here are a few things that I do when taking two rifles in one Pelican case because an empty Pelican weighs more than 20 pounds:
1. Remove one thick layer or two thin layers of foam from the Pelican and separate the rifles using your ammo boxes.
2. Remove rifle slings, bipods, scope covers, etc from your guns, then put those accessories in your checked bag (instead of adding weight to your gun case).
3. All padlockable hasps on the gun case are "suppose to" have some type of lock in them. I use small paddlelocks because the pelican takes four of them and the locks are counted as part of your 50 pounds.
4. Don't have any empty brass in your carry-on bag, the TSA folks don't like this and you'll be the last guy on the plane (although I've always made it on the plane...I don't think they want to pull my checked luggage off the plane due to the additional paperwork or time it takes).
5. I've put partial boxes of ammo in the rifle case several times and they've never once check this or opened the case (let along look in the ammo boxes). I might remove 4-5 bullets to get under 50 pounds if I'm on the ragged edge. I've also put empty brass back in the boxes and it's never been an issue.
6. Don't fully open your rifle case to insert the "my gun doesn't have any bullets in it" signature card. I put two paddlelocks on one end of the rifle case and the other two locks are in my pocket until the signature card is done. I pop open a couple latches on the rifle case (the end that doesn't have the locks on yet) and slide the card into the case, then snap the latches and slap the other two locks on...done deal with no questions asked.
7. Make sure you have a luggage tag inside your rifle case with your contact info (include home and wireless phone numbers) on it just in case your rifle case gets lost. I ended up with an extra rifle case one time; it was strapped to my rifle case on the return trip, the luggage tags were missing from the extra case and there was no way to contact the rightful owner. The chicken scratch on his signature card wasn't doing him any favors. I recognized the case during my initial check in, so it belonged to one of the guys that were behind me in line. I turned the rifle case into airline personnel, but don't know what happened to it after that.
8. I haven't put ammo in a checked bag or carry on bag since 9/11, but I did it all the time prior to then. I just don't want to deal with the potential hassle of a TSA or Airline representative having a bad day and taking their frustration out on me. Nothing worse than showing up for you hunt without bullets!
If you are only taking one rifle, then you shouldn't need to do some of the things mentioned above and you can add a few items to your rifle case instead. I'll put shooting sticks in the rifle case; the trigger sticks I use fit inside the case without removing the V swivel, but V removal is an option if your sticks are too long. I've put my knives and saws in the case (between outer shell and the bottom layer of foam). I've also thrown in a short wooden canoe paddle when headed moose hunting. Be creative as long as you keep it under 50 pounds!
PS - I never dreamed of spening $200+ on a gun case, but it's worth every cent when you pull your rifle out for a test shot and it's still dead on... In the grand scheme of things a Pelican (or equivalent) is probably one of the least expensive items that you're taking on the trip and it's protecting one of your most important items..
Best of luck in your travels.
