[QUOTE=00possum;4133038]What if we used stronger brass to help compensate for the pressure?[QUOTE]

Outside dimensions of the case have to stay the same, so "thick brass" means LESS SPACE IN THE CASE, i.e. less room for powder. Ridge pointed out, that "thick 223 brass is 5.56 brass", and he also pointed out that 5.56 brass runs higher pressure with the same powder charge. So you get about the same power out the front, but thicker brass means you can't load the extra powder you were wanting to load in there, because even less powder fits than before.

As someone that knows a thing or two about Chemistry, this made me chuckle. Technically, ALL of the "chemicals" in the powder "stay dormant until the powder ignites". That's what combustion is, or more appropriately, deflagration - the chemicals are inert until the ignition energy is met and the chemicals react with oxygen.

What you're really talking about is duplex powder charges. Which can be incredibly dangerous. Powder companies "take every dang thing into consideration" when they consider burn rates, from the size of the powder granules to the shape, let alone the chemical composition.

Ideally, to produce the highest velocity possible, a powder should build pressure extremely fast, but then self-limit in some way such that it doesn't continue to build pressure. This would mean the force behind the bullet would build quickly, and push hard with regulated pressure down the entire length of the barrel. That's NOT what actually happens though. Gunpowders are progressive, so as pressure increases, they burn faster. This means that as they begin to reach the max pressure your rifle can withstand, they'll blow right past that structural limit with a smile on their face and blow your gun in half.

You also have to keep in mind that a 22cal bullet is small, and fragile, no matter how it's built. If you overpressure the base, you can damage the bullet before it ever leaves the barrel.

We can, and we have. You'll see 22caliber bullets that have nearly identical profiles (aerodynamics) as larger caliber bullets. The PROBLEM, however, with 22cal bullets is that they are small. To make a bullet tougher, the jacket needs to be thicker so it's less apt to fragment upon impact. HOWEVER, the thicker the jacket gets, because copper (the jacket) is less dense than lead (the core), that means the "SD" sectional density of the bullet decreases. Because the 22cal bullets are so small, they feel the effects of decreased SD by thickening the jacket faster than larger caliber bullets. As sectional density decreases, the more ballistic coefficient suffers, and the worse it will perform ballistically. In other words, it's a balancing act: the tougher you try to make a 22cal bullet to make it better at killing, the worse it gets at killing.

Not the same thing. You could never drive a car to the moon, which is what you're talking about here.

There are limitations to anything. The 223 bullet - or more appropriately, the .224" bullet - can be more lethal by putting it in a larger case, like the 22-250 or .220swift or .223WSSM. But at some point, there is only so much powder that a given bore diameter can burn, and a limit to how much powder can burn through a bore diameter without creating excessive pressure that might cause issues like extreme throat erosion, which is why we start building larger caliber cartridges. 220swift is notorious as a barrel burner, because it's supposedly 20% "overbored" (meaning 20% too much powder to efficiently burn in a 22cal barrel).

And frankly, it's all a moot discussion. A .223rem will kill a deer at 600yrds if you place it well with the right bullet construction (I'm sure it would do further, but that's MY number for it). The margin for error is smaller with a 22cal than it might be with a larger cased, larger caliber cartridge, but it CAN be done. So basically you're asking how to improve a cartridge to do something it can already do.