I had my first catastrophic failure with my B&T APC 556, specifically an out-of-battery ignition. When I pulled the trigger I heard two distinct discharges in rapid succession, my magazine burst apart and the rifle started smoking out of every hole. The bolt carrier group was stuck halfway.
Luckily, I was not injured. I did feel something hit my face. I think it was plastic from the magazine window. I am glad I was wearing safety glasses. So this is also your regularly scheduled reminder to wear proper eye protection when shooting firearms.
Here is what I found upon inspection
The chamber is clogged with the remains of a casing, but the barrel itself looked clear.
The shell around the bolt carrier is cracked and the extractor is just gone.
A piece of the bolt carrier is missing. I do not know where it went.
The window of the magazine blew out. The three remaining cartridges were all damaged.
The failure occurred on approximately the 35th round fired that day, during the fourth or fifth shot of a short firing sequence.
Analysis and inspection
Preliminary analysis by a technician at the gun shop suggests the firing pin may have been stuck in a forward position. This would have led to a premature discharge as the bolt was still locking. The rifle is being sent to B&T in Thun now to see what they have to say about it. At the very least, the bolt carrier group is a complete loss.
Safety features
That said, it is worth noting that the APC 556 did disperse the energy downward and away from me, as a modern firearm should. So in that regard, I can vouch for the APC.
While failures like this are extremely rare, even the most reliable firearms can fail. Always prioritize safety, and never underestimate the importance of protective gear.