Well, here is what happens when someone places a "FX Simulations" barrel on an active duty gun, and that gun is able to chamber and fire a real round....
The FX barrel is designed to fire sub caliber training rounds, and has a bore of about .25 caliber, or so. Should NOT be able to chamber real ammo. This one did. I can only imagine the pressure...
The shooter on the line said he "thought it felt funny", then noticed the magazine had droped out. The case head blew out, damaging the second round in the magazine, and that was it. The barrel and the S&W 59 were undamaged.
Larry