The AR-180 was evaluated by the US military, but they were already well in bed with the M16. The Marines were very interested and probably liked it better than the M16 and they pressured the Army into taking another look at it in 1969…but again, by then we were all in with the M16 and it just didn’t make sense to go back. Stoner took the AR-18/180 design, made it modular and came up with the M63 which was utterly brilliant. Colt did everything they could to kill the AR-18 and were quite successful. Congress passed a law banning sales of military hardware to foreign nations unless it was hardware that is in use by the US military; that killed the AR-18. By the late ‘60’s Fairchild aircraft was in deep debt and not looking good, and started closing down/dumping companies under their umbrella. They had no interest in manufacturing the 180, so manufacturing moved to Howa in Japan. But Japan soon passed a law disallowing the sales of military hardware outside of Japan. So the AR-18/180 was still-born again. However, the Japanese really liked the rifle, and further developed the design into what would become the Type 89 which is still in service today. So the 18/180 found it’s third home at Sterling in England. Problem was, Sterling really had no money and really was a company that would spend the next decade faltering. So when various nations showed real interest in the AR-18, the deal was killed because Sterling couldn’t afford to setup their customers with manufacturing facilities.

Use by the IRA-Provo’s in the late ‘60’s & early ‘70’s made a big impact on the British Army who nicknamed the rifle the “widowmaker”. The Brits really liked the rifle, but they didn’t want to deal with Sterling so they actually had someone steal several receivers from Sterling so the Brit government arsenal could begin building their prototype new rifle. The SA 80 is essentially a very poorly manufactured, bullpup AR-180. Eventually the Brits hired H&K to get the SA 80 squared away and they’re pretty solid rifles today.

So the AR-180 had a tough road. But it would end up being the most influential rifle in the post-WW II period when you look at all the rifles that are greatly inspired by the AR-18/180.
SA 80
SAR 80
Type 89
Australian
Bushmaster 17
Leader Dynamics Mk V
H&K G36
H&K 433
FN SCAR
CZ Bren 802
Radom FB MSBS