There are several brands that I consider "tough". Some are a bit pricey though. I believe I'd look at Warne as a starting point. A one piece (cross-slot type) rail is tough. They can be mil-spec picatinny or just weaver style. Make sure the rings are compatible with the selected base. Here is an example.
http://www.survivalarms.com.au/compo...product_id,395
Ken Ferrell may have one that fits or perhaps a "gunsmith" base that can be drilled and mounted by a smith. Nightforce sells such. Good luck.