I'm looking for the best .243 ammo (the closest to match grade I can find), to fire through a 27 inch custom stainless barrel.  Is a Barnes Moly coated round the best for the application of accuracy and barrel wear?  Any suggestions?
I don't reload - looking for the best factory ammo.  THANKS!

Have you tried Federal Premium?  (The stuff in the gold box.)

I have a hunting grade Remington 700 .243 that shoots very well with Federal Classic 100 gr SP's. At 100 yards this is nearly an MOA combo. I have never tested it for accuracy at longer ranges. The various premium loads using the Nosler Ballistic Tip bullet design should also be very accurate. If shooting at longer ranges I would suggest the heavier loads. You may just have to try out several types of ammo and see which your rifle most prefers.

-Charging Handle

Thanks. . . I have not tried anything yet.  I'm waiting for my Remington 40XB KS in 243 Win.  Should be here in two more months.  The Federal loads are definately at the top of my list.  The 30-06 Gold Medal Match 168 grain BTHP give me sub MOA groups (constant) at 200 yards with my model 700.  I even get a 1 inch group (3) at 300 yards from time to time.  The Leupold 8.5-25x50mm tactical sure helps!

While hind-sight is always 20-20, just think if ya'd order'd that barrel in 260 Remington (aka 6.5mm-08). Ya could have made good use of the plethra of "high ballistic-coefficient" 6.5mm bullets out there and neck'd that 243 brass up to 260.

For 243, I'd definately try the Hornady 95 grn. SST (for hunting applications) and the 107 Sierra MatchKing for accuracy. Whether anyone makes factory rounds loaded w/ these bullets, I don't know, but for the "most" in accurate long range loads, you'll have to roll your own.

FWIW, my custom Rem 700 '06 w/ 175grn. MatchKings put 4 rounds in 3.25" last weekend and one was a flier (wind-drift I suspect), 3 rounds went in at just under 2", so there is a definate advantage to rolling your own., BTW this was at 800 yards.....

Mike