Beat Cop (1991)

This video is notable because it features the first ever appearance by tattooed tough guy Donnie Russo, who would go on to become one of the nastiest muscle-heads in the business. On the other hand, even discounting Russo's debut this one is well worth a look. The action is strictly solo, but it's not your standard jerk-off video by any measure - these guys are built and they are really into what they're doing.