Having owned and built multiple BCM ELW barreled uppers and having built Criterion pencil barreled uppers I would not go there if sub MOA is a NECESSITY.
If sub MOA desired, but sub1.5 MOA is nice enough, and you want super durability I would go DD CHF 11.5" govt. profile barrel.
If you want guaranteed true sub MOA performance I would go with a custom stainless barrel, because you can't guarantee consistent sub MOA performance with a standard barrel, it is all luck of the draw otherwise and then you have to temper barrel profile and material to get as much durability and heat resistance/cooling as possible.
I would go with a Bartlein blank with 400MOD BB barrel material, which has double the life of standard stainless material and get a profile under the barrel of .775" fluted, a 0.750" gas block, and 0.73" fluted forward of gas block profile, with a 5/8 × 24 threading to use .308 muzzle devices to keep as much meat on the muzzle as possible and have Compass Lake Engineering profile your blank. The majority of cost and wait will be for the single cut blank from Bartlein.
I would have a 26" long 1-1.5" straight blank cut in half to make two identical 11.5" barrels. Use a .233 Wylde chamber headspaced to a JP bolt for 5.56 pressure ammo to work out of the box. Use the twist, rifling, and gas port of your choice, but I reccomend a gas block journal the right length for your preferred gas block and a 1/7 5R twist rifling.
That would be the lightest and most accurate barrel possible that was at least more durable than standard stainless. And you would have a backup barrel for when you burn the first one up.
You should achieve a REAL sub MOA performance ALL the time and not just one lucky 1.00" or less 5 shot group per range trip. There is a big difference in an over 1.047" group at 100 yards being an extreme oddity 9 out of 10 times that usually shoots .75" or less and a barrel that let's you put up one Instagram worthy "sub MOA" photo per range trip to "prove" capability. Which do you need?