The action is made from a polymer im afraid, not metal. In theory i suppose it will fire almost as fast as you can cycle the sidelever, but i wouldnt recommend going crazy with it as getting a bit carried away could damage the cocking system.
I had a long chat with the hull cartridge rep about the rifle and it would seem to be weihrauchs answer to competing with the s410 and r10 rifles. I asked him if i already have a hw100, why would i buy this? His answer was "you wouldnt" - which is refreshingly honest. My personal opinion would be save a few more pennies and get a hw100, it is still their flagship model and will be for the foreseeable future, plus they arent that much more expensive.