This is the COM maker stamp. COM GARDONE VT was an assembly shop operated by Contrini Officine Meccaniche di Contrini Giovanni, Gardone VT, ergo, COM for Contrini Officine Meccaniche. It means: Contrini Machine Shops of Contrini Giovanni, in English.

The parts for these revolvers came from an association of Italian manufacturers who jointly produced revolvers for the European and United States market in the 70's and 80s when the demand was strong enough to require a significant production of bottom of game products (low price and quality). The parts were manufactured in the different smaller workshops and then each weapon was assembled under a single brand in the shop of Contrini Giovanni. This did not identify the original manufacturers, only the assembly shop, so it would not damage their reputation.