I know someone must make custom barrels for an AR15 in 7mm TCU or 6mm TCU ??? anybody know? If not, they oughtta!

Why not just run with the 6PPC.  

The case is based on the 7.62x39, which means that you can get stock mags and bolts for the rifle. This leaves only the barrel which needs to a special build.

so the 6mm PPC ctg's can go into the 7.62x39 mags in stock form? are these mags abundant and easy to find? not too expensive?

"abundant and easy to fine? not too expensive?"

Well, they're out there.  I saw an auction for the "Frankenmag" version (30rnder) went for $19.00 just a few days ago.  Watch Gunbroker and Auction Arms.  They're getting harder to find, as they are pre ban.  Now, if you're talking a 10rnder, they're around and plenty of them.  Heck, a drum would work too (hee, hee, hee).

I know that Kurt of Kurts Kustom has made a 6mm BR upper (for the AR15).  If that's your tast....

Edit-
Forgot to say that I'm building a 6mm PPC.... barrel is on order from Olympic Arms. 1:10 SS HBAR 24"

Olympic Arms makes some very good uppers in one or more of these calibers.  Give them a call.

I heard that I can make my AR legal to shoot deer in my state by changing the barrel to a .243 barrel and expanding the neck on a .223 casing and inserting a .243 bullet. The rounds should feed from a standard .223 mag. In case you're wondering it is illegal to shoot deer in Kansas with anything smaller than, I'm not sure of the cutoff but it's around .240 caliber. Stupid law was designed to prevent idiots from shooting deer with .22LR but also excluded the .223 which is adequate for deer with a good softpoint bullet.

The real irony, is that you'd probably be better off using a 64gr power point in 223 than a 6x45 based on the 223 case. I'd go with 6mm PPC if you were doing this so you could hunt with your AR in a state which does not allow 223.

It's a pity no one makes a single shot 243 or 308 AR-15 (as oppsed to mag fed AR-10) upper. (If they can get 50 BMG on an upper - surely you could fit 243 in there.)

Then again - you could buy a whole bolt or lever gun for the price of a custom AR upper.

Unfortunate but true.... we must be AR-aholics if we want to have an upper for everything....

for a budget 6mm AR go with the 6x45. I have an ar-15 and a Remington 700 chambered in this easy to make caliber.  Both guns are sporting Oly arms barrels in stainless.  For deer hunting use the Barnes 85 grain X bullet with about 27.5 grains of Winchester 748 behind it. For varmints i like Sierra 80 grain Blitz King with the same powder charge.  The best thing about the 6x45 is it feeds using standard issue ar mags and its cheap to make and it also packs more punch downrange and makes a bigger hole than the 223.