The rep range that causes the most growth, builds the most muscle, is amrap (as many reps as possible) sets with moderate weights.
Roughly the 20rm, 30rm, and 50rm are the goals here, but a range of 15rm to 100+ is acceptable.
When you’re going high reps, getting a crazy pump and/or activated muscles, and eating high calories you can’t help but be big.
I am very contrarian to much gym knowledge.
My staple barbell movements for you would be military presses, jerks (cleaning into both the overhead lifts), bent rows, shrugs, front squat, and partial front squat, maybe snatch grip deadlifts.
It’d be all for high reps, and there would be a steady diet of calisthenics, jump rope, and isometrics along with it.
(Not to mention machines for the size benefits.)
Heavy isn’t the key for size. The key is reps, volume, and calories.
Go heavy for the rep range and total volume, heavy in a bro science sense meaning effort, not the literal scientific 90%+ of 1rm sense.
This is why I see so many fit dudes wanting to get bigger, but not doing so.
Powerlifting, outside of superheavyweight, is about getting strong while staying a certain size.
It’s not about muscular growth, yet it’s sway is deep in online info.
All the fit dudes stuck at whatever lbs of bodyweight, yeah, they’re not eating enough, but they’re also not taking the % of 1rm that they comfortably train with, and truly making it hard, bringing reps to failure or near it, or truly doing set after set of volume.
They need more calories and more reps.
Size? You could take a low intensity by “scientific” definition, say 70% of 1rm, and using the “bro science” definition of intensity (aka effort), push the reps per set til what is a 10-15rm has become your 50rm.
You’ll be the biggest man around.
Big as hell, and pretty dang strong despite that low % of 1rm.
You’re going to be big and strong using what most stop at 10 reps, could get 15 reps with, but you’re using it as a 30rm that you’re training til it’s a 50rm.
All out high rep set, and/or meaningful volume, plus big calories.
The fit who want to be big would be well served by this.