I've been waiting over a year and a half for my 50 and I'm hoping that it might get delivered sometime around the two year mark. Interestingly, I also chose the Vortex Razor for my build (with a Spuhr mount). I have no doubt that it can take the punishment.
However, while waiting, I started to revisit some of my research and that led me to buy a Zero Compromise 5-27 x 56. I realize that this scope isn't in the OP's budget, but what a scope! When my 50 arrives, one will go on it and the other will go on my PRS rifle. Either way, I don't think I can go wrong!
PS: Here's why a good scope is required. I'm pretty sure this is an AS50. Be sure to watch the barrel reaction at the very end of this short video: