The fact that the purchase price of a double is relatively high is largely irrelevant to me, but the cost of feeding the beast is relevant. I've wanted a double rifle for the past 30 years...buying it is a one time cost but feeding it is a lifetime expense.

I've mostly been looking at the prospect of buying a .470 NE from Searcy or Chapuis, but would ideally prefer a .450/.400 NE for practical use reasons, or a .450 NE because it takes easily obtainable .458" bullets. The reason I am thinking toward a .470 is because Federal makes ammunition for it. I reload but the concept of being able to easily order a box of .470 factory ammunition is very appealing, as is the availability of relatively cheap hard cast .475 Linebaugh bullets for practice loads.

Also when looking at the costs and availability of components for .450/.400, I saw "thin rim" and "thick rim" as well as two case lengths...also noticed several other double rifle calibres with "thin rim or thick rim" and two case length options. Is the thin rim/thick rim the actual exterior rim thickness or does it refer to internal variations of the case? Can the same rifle shoot both or is this another example of non standardization?

Most likely the double would spend a lifetime being used hunting coyotes and wild hogs in Texas...I've been to Africa but never to hunt, and if I ever hunt outside of the USA it will be in Australia (NT) or South America, and if hunting outside of the USA, I will most likely take a relatively cheap and easily replaceable Winchester Model 70. On previous occasions I've borrowed guns from the natives.

Beware, I'll probably come up with a lot more questions before I actually buy one...

Richard.