Everything you read tells you that double rifles aren't as "strong" as bolt-actions and that the best cartridges for them are the lower-pressure rounds like the 9.3x74R, the .470 etc so my question is what happens, if anything, when you see a double with 2 sets of barrels....one a 9.3x74R (lower pressure) and the other a 30/06 (higher pressure)? Does the 30/06 "stress" the receiver more than the 9.3x74R? Another example might be the .470 paired with the 375 H&H. I've even seen doubles, mostly O/U's chambered in such calibers as the 7mm RemMag and the 300 WinMag ???