SG means "small games" the term was coined in India. The cartridge was meant for small deer, hog etc. - Sabyasachi Ghosh. India. [email protected]
The SG cartridge has two Strain Gauge elements pieces of silicon crystal that when compressed or expanded by tiny amounts and also changes resistance
SG cartridge means Strain Gauge cartridge and is distinct from other cartridges. But I don't have that much idea about this but I used to prefer Rio 12 Gauge 2 3/4″ 1280 FPS cartridge and this has a quality of exceptional consistency.