I am looking to buy an AR 10 in 338 Federal what company's offer this product?

You've pretty much answered your own ?

If there are any makers you haven't already found, as little popularity as your chosen cartridge has, being so new & unproved, your rifle will probably have to be a special order item, or a re-barrel of another AR-10 upper.

GunBroker.com, in particular, has only two listings in your chosen caliber, and they are both bolt guns.

On the same site, there are only two offers for your ammo, the price of either which border on the obscene.

Some particular reason for your choice? It definately wouldn't be economy, as there is no source of inexpensive ammo in this caliber. Why not just buy an AR-10 in its' most popular caliber, the 7,62x51NATO (.308Win.)?

ill have to say I have a dpms 308 sportical have no issues at all great gun dpms and armalite are about the only 2 that make a .338 federal unless you get a 338 upper somewhere and make a franken gun. But you cant get the ammo for 13.29 a box like the 7.62x51 natos by aguilla solid brass and reloadable. the .338 would be a waste of money unless you are taking 1000 lb animals, cape buffalo etc., but you couldn't go out and pop up 2 20 rd mags every 2 months. The 308 hornady superperformance packs a 150 gr bullet at 3000 ft pr sc and 2997 ft lbs muzzle so what do you want

.338 Federal is a pointless marketing cartridge that has no purpose that wasn't already adequately performed by .308.

Buy a DPMS LR308 or Remington R-25, but get the magazines first.

Why on earth would want to get one in a 338?? Stick with a .308. Everything will be easier to find.

It would depend on my mood at that moment...honestly. Usually, I'd probably go up to and buy from Salesgirl A just because B would probably make me super self-conscious. But if I was in a particulaily confident (and maybe a lil bit cocky) mood I'd go to salesgirl B.

I have a unfired armalite ar10 338 federal never fired just wondering if your interested?