The only information I can get concerning Hoppes BP solvent ( Elite Black Powder Solvent, nothing for #9 plus) is that its diethylene glycol monobutyl ether <15% and the rest apparently tap water. This from Hoppe's MSDS site.
The chemical is a solvent and is used in Windex (Wikipedia). So you can likely make your own from a bottle of Windex
"The main use of 2-butoxyethanol is as a solvent in paints and surface coatings, followed by cleaning products and inks. It provides cleaning power and the characteristic odor of Windex and other glass cleaners. Other products which contain 2-butoxyethanol include acrylic resin formulations, asphalt release agents, firefighting foam, leather protectors, oil spill dispersants, bowling pin and lane degreaser, and photographic strip solutions. 2-Butoxyethanol is a primary ingredient of various whiteboard cleaners, liquid soaps, cosmetics, dry cleaning solutions, lacquers, varnishes, herbicides, and latex paints. It also seems to be excellent at killing most insects and arachnids.
It is the main ingredient of many home, commercial, and industrial cleaning solutions; such as Simple Green All-Purpose Cleaner which has been used to clean up oil spills. The primary manufacturers are Eastman Chemical, Dow Chemical and Equistar in the United States."
http://www.dow.com/productsafety/finder/egbe.htm#usesSee product uses.
I have been using widow cleaner and water for years 20 or more, as a BP solvent.
Trust me folks its a lot cheaper to buy it as Windex and then cut with 1-2 parts tap water in a gallon milk jug than to buy a bottle of Hoppe's.
I love the things one finds in an MSDS.
I gotta flood coolant system to cobble together and a couple of barrels to order so I better quit.
Dan