Well, new to me anyway...
I bought a HF air-powered brad nailer a few weeks ago. There was no
case, just the cardboard box that it came in.
So I've got a nailer, the little bottle of oil, a wrench and a few
boxes of brads to store.
That's when I remembered that I had kept the case from a Dewalt
Cordless drill that bit the dust a few years ago.
I opened the case and laying the nailer on top of the molded plastic
inserts, I determined how much of the inserts to cut away so that the
nailer would be held firmly in position. I grabbed the multifunction
tool and using the angled cutter, cut the inserts flush with the
bottom of the case. It cut like butta' ;-)
I then laid some scrap foam in the cut out area and put everything in
the case. I left some "cubbies" for the brads, the oil, etc.