Two questions.

Can a berreta O/U in 30-06 be rechambered to 30r blaser,300h&h rimmed or another rimmed 30?

Can a searcy or merkel 375H&H mag be converted to a 375 flanged?

Someone here was talking about a 458win being rechambered for a 450 no2, this is what's got me thinking.

As an aside, I was in the H&H gun room in NYC this week and I saw a beautiful rigby sidelock 1912 in 450ne that had been rechambered and rebored to 470NE. They wanted $55,000USD for it. I was pretty surprissed, does that not seem just a little (2x to much) steep?