[Hacker15e]

I think you'll find that getting a helmet for civil flying is going to end up being expensive no matter how you look at it.

Anything you get military surplus will need some work to change over the military stuff to civil impedence (if it works at all).

Usually military surplus stuff will have torn/worn leather edgerolls or cracked/damaged shells -- the USAF treats the helmet shell itself as essentially a fly-to-fail item and replaces the whole thing when it gets to be too tattered and torn. If you want to refurbish a well-used military helmet I know of several people that do it (and do a very nice job), but it will cost you.

If you buy something new, you'll pay every bit as much as you would to "restore" one and more.

Are you planning on using it for flying?