How many times can you reload brass

[Sunray]

"...is their(sic) a magic number..." No. Case life is entirely dependant on the load used. As mentioned, with target loads(no crimping on those), the case mouth will crack from repeated loading before anything else will happen.
"...if you were to load cracked brass..." Burned hands at the very least from the gasses blowing out both ends of the cylinder.

 

[Dudedog]

You can use pistol brass until it fails from splitting or the primer pockets getting loose.

I don't even bother counting the number of times I have loaded 9mm or .45 brass, I just use it until one of the above happens.
Pretty much the same for light-medium .357.

 

[cougar1717]

Brass inspection is important as there is no rule of thumb. Reload them until they show signs of failure or you as the reloader do not feel comfortable with the amount of stretch or wear seen during inspection. Just remember, one or even a whole batch of brass is cheap compared to the healthcare costs of an accident or damage to the firearm. With low pressure handgun cartridges or even downloaded target handgun cartridges, you will literally lose the brass before they are used up. Revolver brass will either split upon firing along the body of the case or the mouth of the case will split when belling during reloading. Pistols without fully supported chambers create "pregnant" brass. The brass has yielded at that point where it had to contain the pressure without support from the chamber. Continuing to reload and fire the same brass in an unsupported chamber increases the likelihood for a KB. Rifle brass or bottlenecked pistol brass are a little different and will usually split at the mouth or just above the head where the brass stretches. Again, inspection is the most important part of safely getting the maximum life out of brass.

 

[Big Wes]

Case Head separation is not to be taken lightly. I blew up a Glock 30 due to case head separation, not fun for the gun or shooter, the first thing I did was look to see if I still had hands. (scary stuff) My opinion, It's better to be cautious and perhaps set a limit as to how many times you reload a piece of brass. It's better to be safe than sorry.

BTW I sent the Glock 30 to Glock and they sold me a new one for $350.00. They also mentioned that I could have any caliber they make $350 delivered to my door.

 

[spitballer]

I reloaded .223 cases 6 times or so before the necks got hard, until I went with an undersized neck when I had my barrel replaced. Since then I get closer to 18 or 20 with NO annealing, believe it or not. However, new cases can still be ruined by maximum experimental-type loads after one or two loadings, I found that out. Be safe!

 

[1911 guy]

Completely agree with the others who have posted, there is no magic number. It depends on too many variables to have a hard number across the board. However, you'll eventually find some generalities that apply to each caliber you reload for. For example, .45 auto gets reloaded until i lose the brass, .223 gets split necks after a little more than a half dozen loadings and .308 starts to get a "ring" inside that is felt with a paperclip inside the case after about five loadings. Those are applicable to only my loads in my guns, however. You'll eventually find your own. While brass isn't cheap, replacing brass is still cheaper (although less exciting) than having case failures.