AR47vet

I hate to say that while I am super versed in the AR15 and its offerings, I am not to rightly sure as to what big bore calibers are offered for the AR10. Hence I am here asking the AR10 guys.

I am looking to build myself an AR10, I have built 2 in the past for friends. Both had them chambered in 308, standard fare. Now I have been all over the net, as many barrel manufacturers as Google can turn up, and all I can find is 22 250 270 308 and 6.5 these days. Now I like my larger Diameter bullets like .40 and up. I was wondering if there is a 40 cal chambering for the AR10? And if yes, where may i be able to find a barrel? Much thanks in advance.

Just doing the required new guy thing is all. Just have some caliber questions. Been shooting and building ARs for about 7 or 8 years now