Bigherm is a freak. I looked at Winstrol (winny) and var and gained 16.
MarkyMark probably weighs 170lbs and jumped up to 180 lean. Most actors are little guys, but some one like The Rock, impressive, I think the movie was called FASTER, dude was looking massive.
But it's pretty easy for guys between 5'3 and 5'8 (no offense to anyone) to look noticeably different from 10-20lbs. I'd say it's just as common for actors to run gear as it is for the average guys in the gym, they either have a connect, and/or hire a nutritionist who is the connect for many movie roles. Many times guys have 6 months to a year to prep for a movie, sometimes only a few weeks, but they generally know ahead of time where they need to be and can pay someone to get them there.
Like CFMike, I can jump around from lower 200's up to 240's and probably a little further if I really tried, but at 6'0-6'1 sometimes 10-15 lbs doesn't look like a lot on a guy, unless you already have some years under your belt and have a muscular physique, then you notice the size. Anymore I prefer 225-235, pretty easy to hold and still able to move, but I also don't mind being around 210 and more athletic, as long as I hold the muscle size of a little heavier weight.