I've had one squib load in my life. The round was a remanufactured 9mm from a vendor I'd rather not specify as most of their ammo has been great. Luckily, I noticed I had a click but no real recoil as I was shooting so I stopped, unloaded and checked the barrel. Would have been nasty if I'd been firing in fast repetitions but it was easily rectified and the vendor gave me a box of 50 for my troubles when I reported it.