Just to reiterate it for future readers, as you were clearly not the first to to it with your gun: When you fired the rifle using 22 lr ammo, it blew up.
It looked like "automatic ejection", but that's not what was supposed to happen. The breach block broke off, and the extractor pulled the case. As the breach block flew away, so did the case.
Flobert ammo is much weaker than even modern 22 short ammo, it's basically a bullet on a primer cap. Unless it's clearly marked as 22 long rifle, don't use it with modern ammunition.
I used to love being able to hit hard at 1000 yards. As I get older I find hitting a mini ram at 200 yards with the 22 oddly more satisfying.