I as well as many others have pondered what the AR-180 would have become if it had the same development as the AR-15.
I think I may have found the answer.
The Remington/Bushmaster ACR Advanced Combat Rifle
Designed by MagPul and named the Masada the rights were sold to, and the civilian version is made by Bushmaster.
I snapped a few pics before I left town but it has many features that are directly decedent from the 180.
More pics to come and I hope to get them both to the range to compare them side by side.
Some of you may recall a post some time back with a mystery bolt that a reader was trying to identify.
He just sent me an email and said he found out what it was.
A Bushmaster Assault Rifle.
A very interesting rifle with concepts taken from the AR-180 and the long stroke piston design most commonly seen in the Kalashnikov rifles. I particularly like the captured recoil spring. It looks like something I could build in my shop at home.
A fantastic dis-assembly post over on AR15.com can be found here.
For anyone who might be interested, there is a new in box one for sale on gunbroker for a very reasonable price. Click Here
These rifles never caught on and like the AR-18/AR-180, they never got the years of refinement needed to make them truly great rifles. They both however, show many of the design elements found in modern rifles like the SCAR 16, the HK G36/SL8-6, and the Magpaul Masada/Bushmaster ACR.
Photo above showing the SCAR 16 and SL8-6 was found in an excellent article on The Truth About Guns.
Photo above showing the Bushmaster ACR bolt carrier group. Credit unknown.