WW7, That is the Viper Predator Pro-MT. My Allegiance is shooting 301 and there is no pin crowding. The pin gap on a bow is the same as one shooting 285 to 310. I know this from shooting an adjustable 3D sight, the Tox with a Boss Scope. There was 3 lines of adjustment from 20 to 30 and 3 lines of adjustment from 30 to 40 and 4 lines from 40 to 50. That was the same on my Vortec (285 fps) as well as my Allegiance (301 fps).

Here is the link for my review on the Viper sight: http://www.huntingnet.com/forum/tm.aspx?m=1577393&mpage=1