Chambering Round, Not Firing It
 

Is it bad to chamber a round over and over but not fire it?

In terms of carrying a bullet in the chamber for about a week, removing it, going to the shooting range, firing a different type of ammunition, then putting the original bullet back in.

It won't matter in a revolver, but it can in a semi auto. As the slide slams the bullet into the chamber, it may set the bullet back a bit in the case. Do that a number of times, get the bullet far enough in the case, and you can wind up with an overpressured round.

I keep a cocked & locked 1911 on the nightstand. If I unload it for any reason, I put the chambered round in the bottom of the magazine and load a new cartridge. I also make sure to regularly shoot the ammo that's been in there so that it's all rotated.

With mine I just measure the ammo that I have chambered a few times with a caliper. If isn't shorter than the untouched stuff, it's GTG. A couple thousandths of an inch shouldn't be a big problem. So far I haven't observed any ammo setback with my SD ammo. I keep an eye on it because 40 S&W has apparently developed a reputation for being a PITA about it.

i also measure mine and check them so far i havent ever noticed any setback in my SD rounds. it happened a lot with hp ammo years ago. but its a good idea to either cycle it out like CA does or measure it.