If you have 'cannonball delts' but didn't used to have them, did you do exercises that directly targeted the lateral deltoids, e.g. lateral raises, upright rows?
Military press, arnold presses, clean and press, upright rows front raises and side raises.
Bench - 355
Squat - 405
Deadlift - 600
Making sure you aren't overtraining is essential. Your delts are a relatively small muscle group, and get hit hard in both your chest and back workout. If they aren't growing, I suggest working them with one of these bodyparts (or in less volume on both days). When I started training this way, my delts got much fuller.
As for excercises, I think wide-grip upright rows are absolutely essential. For me, they are the best exercise for targeting side delts. Side raises, front raises (if you think they're really necessary). All sorts of presses, but I prefer to use mainly dumbells, as they are easier on your shoulders. Shoulders are easy to injure, and that can keep you out of the game for a long time.
I wouldn't necessarily state that my delts are 'cannonballs' but they are one of my better body parts and have seen the most improvement since I've changed my philosophy on training them.
I use to hear people say that all you needed to do was go heavy with the shoulder pressing movements. I had gotten to the point where I was able to press the 105 lb dbs for a few reps. I had later gotten tendonitis in my elbows and changed my delt training style.
I was forced to go lighter on the pressing movements, but still tried to go as relatively heavy as i could without aggravating my (elbow - tricep) tendonitis. During this time I had also started to include a lot more wide-grip upright rows. And many versions of the lateral raises - from heavy cheat reps to higher rep strict reps,to leaning away lateral raises and other variations. My delts had become significantly wider because of this and during this time ironically my pressing strength isn't at it's peak, but i think overhead pressing is slightly overrated in terms of overall development.
I also think the rear delts are highly neglected and reverse fly's arent the best exercise to develop them. I would look into face-pulls. When I started doing face-pulls the development in my rear delts was extremely noticeable. The front delts get hit to a degree in any upperbody pressing movements, but the side delts are often left understimulated. I think isolation is a must for the side-delts.
what most people dont realize is that well developed rear delt will def give the cannonball appearance. Most people give very little effort to their rear delts. They also go way to heavy on rear delt exercises. It is a small muscle that really needs to be worked by lowering the weight and squeezing really hard at the top. My shoulders have changed dramatically since i started training like this. M