Re: 4-16 or 6-24 Vortex Viper PST
I have 2 of the 4-16 HS versions and they do everything that I need. I have taken them up to 700 and have taken moving game at 500Y. I can see out to 1000 and beyond, just havent had the opportunity to set up a target at 1000.
The reticle on both scopes(HS and PST) is thin enough not to obscure the target and the clarity is nice for the price. Honestly I keep my scope dialed down near 10x for most of my shooting as it is brighter and mirage can be unbearable in the summer (over 100 F).
IMHO the 4-16 will be perfect for 500 and even take you to 1000, but it really depends on the type of shooting you will be doing. We all like to say 1000, and if your range has steel set up at 1000, then sure a higher mag scope will do fine. I just find the smaller field of view and mirage annoying.
My point is you will be well served with the 4-16, but if you want higher mag I would look at the Razor or a NF, the PST and HS are nice but they are no NF.