Vafish is correct in my experience. I do know that closing the action hard without the barrel installed absolutely WILL wreck a S&W 3000 shotgun (the Howa-made clone of the Remington 870, sold under S&W's banner in the 1980's). It destroys one of the shell latches (the one you can't get anymore from those who still have parts for the gun). I've never done it, but I got screwed on an internet auction where a like-new 3000 was sold to me at a suspiciously low price. Turns out the latch was bent beyond repair. Oh, well. It made a nice "parts gun" for my two other S&W's, and I got a pristine rifle-sight barrel out of the deal.
Like Vafish said, just go easy and you won't damage anything. No reason to slam things around.
Glock 17, 19, 21SF, 26, 37, 39
Glock Advanced Armorer (AA), Glock Instructor Workshop (IW)
Remington 870, Benelli M1, Smith & Wesson 3000, Mossberg 500