First off, I'm not picking on you Chris, it's just that I hear this statement from people all the time and am responding to it in a general sense. My comments are not directed specifically at you.

This logic is "post hoc, ergo propter hoc" and, as usual for it's kind, is indicative of cognitive dissonance. The answer to your question is - "Of course they would!" Modern double rifle manufacturers do many stupid things, and the fact that they do so has nothing to do with technical propriety. Most of them will also fit beavertail fore-ends to large bore double rifles - some of them only fit beavertails. Do they know better? Sure, but what has that got to do with it? They build them due to market demand, not because it's a good idea.

Today's DR manufacturers are up against it. The market is small and competition high, and that market isn't as sophisticated as it once was. Like anything else, what the makers build is dictated by demand and that demand is created by many folks who don't know any better because they don't know any different. The makers build what they can sell. I know plenty of guys who wouldn't dream of buying a double in .375 Flanged Magnum because they can't buy ammo at Wally World like they can Belted Rimless. They'd never dream of tolerating the inconvenience of hard to find ammo. They have no idea how inconvenient it will be when the extractor pawls wear and begin to fail. Same guys want beavertails to protect their fingers from the barrels when they get hot. When the overloaded solder joint on the fore-end loop fails and the loop shears off, putting the gun out of action completely (cocking rods don't work, it doesn't go "BANG" anymore), they condemn the maker instead of themselves for having been uninformed enough to have ordered it that way to begin with.

Based on my own observations over the years, there's no doubt in my mind that doubles chambered for high-pressure rimless shells do come off-face faster than those chambered for shells designed for doubles. I've sure seen a bunch that were loose. The loosest double rifle I've ever examined was a relatively new Chapuis .375 H&H. I haven't fired many rimless double rifles as I avoid them like the plague, but I uniformly had extraction/ejection failures with those that I did shoot. I know of sheared fore-end loops on recent beavertailed DRs from several makers. All of these problems are easily avoided by avoiding such chamberings and designs. Geehawed mass produced bolt rifles are one thing, but setting up a double rifle for premature failure is especially senseless.

As to the discussion of pressure, it's worthwhile to note that most of these DR cartridges were created and standardized by the British. The British approach to rifle cartridges was, to my knowledge, unique in that they ignored chamber pressure and measured only bolt thrust. Their rifle cartridges were developed and standardized in base crusher guns, which measured bolt thrust by the base copper units of pressure (the copper cylinder was crushed between the case head and breech face) yardstick. The cartridge being tested was greased before firing to eliminate the ability of the expanding case to grip the chamber wall.
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