From an old IAA FORUM discussion:

The Grand Technologies Group (GTG) was incorporated July 1981 with the principal activity being the development and potentially marketing small arms systems using folded ammunition.

.50 Cal. Omega Cartridge.
Development of folded ammunition in a larger [than 5.56mm] is currently [1983] being conducted. This research is under the title ‘Omega Project.’ At this time, the primary aim of the Omega Project is to produce a folded type cartridge which is the ballistic equivalent of the .50 Cal. M2 ball round. When these requirements are met, the cartridge will be further developed to produce the same ballistics as the .50 Cal. M2 ball round, but of recoilless design. This recoilless .50 Cal. Omega Cartridge will then be adapted to a shoulder rifle. This rifle will enable an individual to comfortably fire a projectile with the long-range accuracy and hitting power of the .50 Cal. M2 ball with target rifle accuracy. The rifle will not weigh more than 20 pounds. A small quantity of Omega rounds was manufactured during the summer of 1982. The cartridge has since been redesigned to ease production. Firing of the .50 Omega M2 equivalent is expected mid-summer [1983] and firing of the .50 Omega recoilless is scheduled for the end of the summer.”

Note: Frankford Arsenal began work on folded ammunition in 1965 to study the feasibility of a recoilless rifle. The cartridge was designed by FA engineer Andrew “Andy” J Grandy, who went on to found Grand Technologies Group, Inc. to continue his work after FA closed in 1977. According to the document above, 500 rounds of grey PVC Omega dummies were produced in 1982 for cycling tests, as were 500 rounds each of live aluminium and inert aluminium rounds.