This isn' the first time I have built a .50 rifle. Did a bolt gun a couple years ago. Looking for something more challenging now. Just happen to own a Serbu as well.
There is a first time for everything. If you do it the right way it isn't anymore dangerous than crossing the street. Common sense prevails here, I can assure you I have no intention of being nominated for a Darwin award.
As far as the Serbu injury is concerned it was on a very early shell holder model. Not even close to the bolt gun he went to production with.
Part of the satisfaction I get from this sport is putting a personal touch on my tools, not just the spacing between the holes I make in the sheet of paper downrange. If all I do is shoot something someone else built for me, more than half the fun is gone!