Hi Obie.
So far I haven't had to open my duffle bag at check-in. Most of the time they look a little bit curious when they feel the box inside the bag, but only once have they asked me what it was. I just said it's a steel container I use to prevent fragile things from breaking.. They didn't ask me to open the duffle bag.
I bought the box in a army shop for 6 Euro I think.. I had planned to spray it black, as it looks a little better if I will have to open my duffle bag in a security check.. but as with so many other things I plan to do, It hasn't happened yet :)
I have several different ammo cases like this and I thought I was quite clever when I made some adjustments and made them lockable, but I later found out that someone else had already thought of it.. :(
http://www.ammolock.com/images/padlock.jpg http://www.ammolock.com/images/50cal.jpg
AmmoLock