After looking at a posting about corrosive primers a couple weeks ago I remembered recently seeing this auction and posting the same pic there. The funnel is part of an accessory kit that came with a cased
British
sporting rifle.
Pattern14, look about 4/5 down the auction page. The cleaning instructions are posted inside the case!
http://www.auctionarms.com/search/di...8962&oh=216543
Lancebear, no, Hoppes alone is no good. The older bore formulas were water based and would work, but you had to repeat until all salts were removed. Hot water porued down the bore should be enough to get it all first time.
A funnel like shown shouldn't be hard to make. Steel parts that would blue or parkerize wouldn't be practical. Hard to work and will rust to boot. Make one if you are handy with a fired brass cartridge case, a length of copper tubing, and a funnel. Drill out the primer pocket to the OD of the tubing, bend the tubing to clear the reciever, add an inexpensive tin funnel from the local hardware store. Glue or solder the 3 parts together and you are done. If you want, you can have it plated for looks, but that would be cost prohibitive and not necessary for function. I would almost guarantee that is how the one pictured was made, but they probably used a copper funnel and soldered the parts together.
HTH,
Emri