^Of the 3 empty cartridges i have left one ways 7.7g, one weighs 7.8g, and the last weighs 7.9g...i know for sure one of my filled one was also 7.9g and the other 2 i'm not sure as i didnt really think to weigh them b4 filling back then.
So from my experience 7.7-7.9g for an empty...