It’s spelled “Tec-9”
Tec-9 are notorious for jamming, due to their large magazine capacities, and poor quality.
There is a song by Boogie Down Productions, in which the main character meets a boy named Rob, a drug dealer, who sells drugs on the main character’s building complex.
The last line is talking about rocks. KRS-One is a rebel since he is the holder of a boulder, must rebels just have stones.
This was during a heated up argue between Scarface and Alexandra Sosa. Chi Chi which is Scarface’s assistant would later take the phone away from Scarface and calm him down. Happens near the end of the movie.