From time to time there are threads about proper jags for doubles.

I tried several different jags (none made for a 470) before I purchased a Parker Hale rod and Kynoch jag from Trader Kieth. They are a little pricey but worth every penny. The jag fit perfectly and the rod is very stout.

I bought it at DSC and they were a pleasure to deal with. Now all I need is a couple of the leather rollups for my scopes.

I wish there was more information on cleaning doubles of different calibers. Sizes of Jags, how to clean, chemicals to use etc. are all just left to discover on your own. Given the expense of these rifles it would make sense to protect it properly.