Just like the title says: I need a gas block for a .750 diameter barrel, and a rifle length gas tube. Although Brownells has new DPMS blocks for around $25.00 (without tube) the shipping and handling raise the cost considerably. I figure someone near Portland has to have an old gas block and tube that they aren't using, and would want to sell, or trade. Cash is always an option, however, I have other AR parts and other items to trade. I'm in the Portland metro area. Actually, I would like a gas block with cross pins to secure it to the barrel such as on an older front sight tower. I have one of the .625 sight towers, but obviously, it won't fit my barrel. I don't mind used parts as long as they are serviceable. The primary problem with some old gas tubes is that the knob on the end that enters the gas key gets worn...but that is really easy to see if you just make sure that the knob is there all the way around the tube.