Microtech Small Arms Research went out of business a while ago, but their website is back online and the new owners are bringing an updated version of the STG rifle to market.
The STG-E4 is patterned after the Steyr AUG. It will be available with either .223 or .300 AAC BLK barrels. The fluted barrels are available in 16.5”, 18.5” and 20” lengths. It uses a standard AR-15 magazines.
MSAR used to be a strange company. They got little press from bloggers because they put up a big notice on their website saying that everything on the site was copyright and they did not give permission for it to be used in any way. I emailed them once asking permission to use photos on TFB, but got no response and so never wrote about them.