You sure that wasn't AP ammo?
>My understanding is the original M59 ball round was steel (or perhaps Iron ?) cored. It may also have been considered to be semi AP ?
A big part of that is the FAL getting the British/Commonwealth contract. The AR-10 had a lot more competition than the AR-15 did, while coming out years after it's competition was already settled into the market. Plus it had a number of early quality control issues, which killed a contract and of course US government interest. Then there were the political issues, like the US embargoing sales to Cuba despite the interest of the regime in it, and the Netherlands banning weapons sales to Portugal (the Dutch owning the contract for sales in Europe).
>Yep, my understanding is that the Commonwealth designs also modified (and probably improved ?) the original FAL design somewhat.
Its a shame, because it apparently had some advantages over the FAL:
https://en.wikipedia.org/wiki/ArmaLite_AR-10
>Yep, today I would probably choose an AR-10 style rifle over an FAL style Rifle if I wanted a semi auto 7.62 x 51 rifle for Civilian use. At the time I can understand why the FAL was originally chosen.