What happened to Scott sucks. This wasn't a fault of the rifle, just poor ammo of questionable origin. Seems like his dad does majority of the filming? Glad he's alive and has a great morbid sense of humor.
I feel for Mark Serbu. If I built something like this that caused someone injury or untimely death, I'd be depressed too. Hopefully he can get some closure when he gets the rifle and the SLAP ammo Scott had to do a full investigation on it. Only good can come from this. The small amount of bashing I saw towards Mark was really unwarranted. Scott even said this was not fault of the rifle.
It's not about bashing anyone... It's not the rifle's fault, just like it's not the car's fault if a drunk driver hits you in a frontal collision. Yet, it makes a big difference to you if the car has seatbelts, airbags, and a collapsible steering column instead of having an old fashioned steel rod aimed right at your chest, with nothing to hold you back.
There is a big difference between building firearms, and designing firearms. You can be a very good builder, machinist, and metallurgist, but a poor designer - and vice versa.
Paul Mauser spent more than ten years refining his bolt action design, and still lost an eye
after finalizing the K98, with one of his own designs blowing in his face (the C98 prototype, a semi-auto design). After that, he became really anal about safety...
John Browning also spent decades refining his designs, and produced a few very iffy models before ironing out some major safety issues.
Today, we have the advantage of more than a century of experience to draw upon, so there are no excuses for overlooking critical issues. The correct answer to safety is not "Overbuild it so it won't break/blow/fail", it's built-in redundancy, and safety mechanisms or features meant to avoid or minimize the consequences of a catastrophic failure.