madcratebuilder's recommendation to visit the Sadlak Industries website would be my choice as well. Take the time to read the entire article in the link and you'll understand why. A close second is the Smith Enterprises
product. Spend the money for steel or titanium... aluminum will not survive hard use for very long.
As to the scope...
. Sorry, for such a grossly vague inquiry, I'm not going to bite on that one.