Oh I have a 308, 243, and 3030 for deer. It's not about shooting those ranges, it's just wanting to maximize something everyone is familiar with. I just want to do what others haven't. Plus ammo is cheap, recoil is minimal, it's common, and just a all around fun gun. I wouldn't mind hunting at extended ranges. It's just getting there and getting good at it.

I've probably taken over 100 deer with a 223, yes they kill deer, yes they will kill a deer at 500yards if you hit them right, but you won't find but a fraction of them.
I've killed a lot of deer way beyond 500, many past 750, more than a couple past a grand, so this is what I have found from shooting deer with a 223 and at extended range with other rifles.
1) the first blood you will normaly find will be after you see the dead deer shot with a 223
2) they will all run with a 223 unless you take out the CNS (brain/spine)
3) at 500 yards your deer runs out of sight it is extremely diffacult to find where the deer was standing at the shot without snow cover and still hard with it
4) the more distance increases the more it exacerbates #3
5) there are no bullets suitable for deer made in .224 that have a high SD and BC which is what you need for long range accuracy
if you shoot 1/4 moa from a bench at 100 yards, and at 500 yards your shooting 1MOA, most likely the bullet is a lower BC/SD bullet which just doesn't fly well as range increases, I have proved this many times with many rifles.
take a fast twist 223 loaded with a 75 gr a-max and its fun to shoot targets at 750, but the 223 will never be a 500 yard deer rifle with todays technology, nor in the foreseable future.
Its just the way it is
RR

I haven't tried to drive a car to the moon, but I've driven a car enough to know it can't get me there, even if I fill the tank with rocket fuel. As much as that is a smart-@ssed remark, it's the truth of what we're talking about here.

You're FAR from the first guy that has sought out high ballistic coefficient bullets, running really fast, even in the .223rem. That's why you see new bullets like the VLD's with improved BC's and why you see guys blowing out the shoulders on 223rems to create 223AI's. ONLY SO MUCH POWDER FITS IN THE CASE, THE BULLET IS ONLY SO BIG, AND THE CASES/RIFLES CAN ONLY HANDLE SO MUCH PRESSURE.

You can never drive a car to the moon.

Once you've achieved maximum velocity with a case full of powder, the only way to increase the velocity is to use a faster burning powder. With the faster powder you'll get higher chamber pressure, the problem lies with the pressure curve. If you graph the amount of powder used and the pressure it creates, you'll see a linear increase in pressure as the quantity is increased, up to a point. Once pressure hits a certain point it changes the way the powder reacts, and the pressure curve takes off like a rocket. I have no doubt that in the future smokeless powder will be looked upon as a primitive weapon. Some chemist will discover a propellant that'll drive bullets like a laser beam, and new barrel steels will be created to handle the extra pressure. Until then we're stuck with our current limitations.

That's much easier to accept. Now I don't see this working, but here's another wild idea. What if you use a gas or a liquid propellant? Like mini acetylene tanks maybe?

ok, I just wrote this thread off as hopeless.
RR

Solid propellants are used because they have the highest stability and energy density. A 'mini acetylene tank' the size of a cartridge case woul hold LESS POWER than gunpowder.

I'm checking out of this one as well. It was a fun goose chase at first, but now we're chasing ostriches with laser eyes. As a new technology development engineer, I often use this line: creativity, ingenuity, and innovation are never to be confused with bong water fantasies.

M855 and M193 is ran at higher pressures than your 223 remington.

I shoot alot of M855, and can hit "area" targets with it at 500meters.

Man's torso is hard to hit but very doable. 55 and 62gr are really designed for 300 meter human targets and 400 meter area targets.

But like some said, if you load 75gr high BC, 500 meter human torso targets are extremely doable.

Likewise for reasons being discussed here, I will be purchasing a .308 AR 10. I could give all the obvious points as to why but will add that as a reloader...I can load light .308 ammo for plinking and still be more powerful than any .223 ammo.

Or conversations that go like, "Well, don't try this, but one day bill decided to try this, and at the funeral they had a closed casket because...."