Sylvester Stallone isn't pulling any punches over his dissatisfaction with where the 'Rocky' franchise is heading -- once again publicly lashing out at one of the OG producers.
Sly went on the attack for a second time this weekend, posting a very scathing message aimed at Irwin Winkler ... who helped get 'Rocky' off the ground way back in the day, and who apparently has an ownership stake in the IP -- while SS has none himself.
That's where Sylvester's beef lies, and he made it clear in yet another critique on Instagram .