The higher level launchers are designated either M1 or M3.
M1 uses M1 torps.
M3 uses M3 torps.
Then both M1 and M3 torps come in 3 different mods.
Mod 1 - Average speed, long range and low damage.
Mod 2 - High speed, low range and average/high damage.
Mod 3 - Slow speed, average range (still high compared to other nations) very high damage (almost sub levels of damage per torp)
M1 and M3 torps generally follow the same ternd with M3 torps having generally shorter range but more power.