Not handloaded - because it happened with 22 LR

[Sverre A.]

I was shooting CCI Green Target, and after 60 shots - "a wind" blowed into my face.
The bottom of the brass - was gone.

I`m glad that I always use shooting glasses 

[stimpylu32]

While case head separation does not happen very often with rimfire rounds , it does happen , and that's why we need to always wear shooting glasses , glad your OK .

You could shoot another 10,000 rounds and it may never happen or you may shoot only 1 , so like the Boy Scouts say - Be Prepaired .

stimpy

[bilmac]

Don't remember where I saw it but I've read that storeing your bullets anywhere around cat boxes will weaken brass because of the airborn ammonia.

[Catfish]

I think Bill hit it. I would definately have the head space on that rifle checked. If you ever gat any miss fires with it I would bet the head space is bad.

[Sverre A.]

It`s not a rifle but a Marvel conversion unit for my STI Targetmaster.

[R.W.Dale]

 Has anyone anywhere actually had a firearms headspace "go bad" It's not like milk people headspace doesn't just go bad without a very good reason. If you have a firearm that suffers from an excessive headspace issue there's a 99.985545% probability that it left the factory that way.

[torpedoman]

usually a semi auto problem the chamber gets dirty and the round hangs up going in and the bolt is pushing on the rim and the rim is the primer.

[Savage]

Has anyone anywhere actually had a firearms headspace "go bad" It's not like milk people headspace doesn't just go bad without a very good reason. If you have a firearm that suffers from an excessive headspace issue there's a 99.985545% probability that it left the factory that way.

Exactly!!  Not a rimfire anyway.
If I were a betting man, my first choice would be a dirty chamber. Second would be faulty ammo. I think the second is highly improvable as CCI is some of the best rimfire ammo available for the price.
Savage

[Sverre A.]

"If I were a betting man, my first choice would be a dirty chamber"

Glad that you not are a betting man  . 
But if you mean that firing 100 shots before the blow-out can cause a dirty chamber - you can still be a winner 

I think it caused faulty ammo.  After the blow out - I cleaned the gun - and shot 500 rounds with different ammo (also empted the Green Tag box) without any signs of trouble  .