Gun case lining

[Stu]

I've a friend in the cabinetry business whose offered to build me a case so he can try out a couple of ideas.

The only drawback is he's insisting on lining the interior in leather. I'm assuming this is a bad idea based on the fact that a) all the cases I've seen have some type of cloth inside and b) storing a pistol in a leather holster isn't a good idea, so a leather lined case would be no better.

Would anyone agree with my gut feeling, and could they give me a reasoned argument against the leather interior, (will trap moisture against the gun etc).

What would people recommend as the ideal lining material ?

Thanks for the help, Stu