Guys,
An 80 grain bullet weighs 80 grains. It does not matter how dense the material is. It will occupy less volume, but then you won't be able to optimize the front end. Remember there is a rule in bullet making. The OAL of the bearing surface(the shank) has to be at least as long as the bullet is wide, so that it doesn't try to get sideways in the bore. A .308" cylinder that is .308" long has a volume of .0229 cu. in. Uranium has a density of .676 lb/ cu. in. The shank would weigh 108.59 gr. You could do some type of wasp waste to reduce the volume and keep the shank OAL the same but it would screw up the aeros and reduce the BC. Area Rule works in supersonic jet fighters but is worthless in bullets. They do not have wings.
I have experience with poly materials. When you use them as the leading edge at Mach 3+ velocities they begin to change shape after about .5 seconds flight time. The temperature builds to above 500 deg. F. at the leading edge, dependent on the tip shape, and combined with the tremendous back pressure it is sufficient for even the most high temperature resistant poly materials to begin to flow. The result is at that point the BC begins to decline.
The only way that I can see to get a 1.0 BC with a 30 cal. 80 gr. bullet would be to add thrust in flight. If you machined a combusition chamber into the rear half of the bullet and a very precise nozzle, then filled this with solid propellant, maybe you could get enough thrust to get the equivalent of a 1.0 BC trajectory. But with this configuration you can forget anything like what we would call accuracy. The ignition delay parameters and the burn rates would not be nearly precise enough. You can get much better control with liquid propellants but that requires pumps and regulators. Besides that, all this fuel and stuff is extra weight.
If you use a sabot and subcaliber the 80 grain projectile you can do it. If it is spin stabilized it will only be as accurate as the shoe material will allow, which is generally not great accuracy. It is more accurate to fin stabilize a subcaliber round, but you need a very high sectional density, >.600, to overcome the drag the fins add. Also, you need a smooth bore.
The point I am meandering around is that it is tough to repeal the laws of math and phyics.