I'm brand new to PRS shooting my first match on Sunday going thru the rules I can only have a bullet that goes less than 2800fps and 178 and under so the question is WHY? If the bullet is heavier I have to make adjustments for Elevation more, if lighter you need to adjust more for windage soo? and no matter what lighter or heavier 2,800fps applies so what am I missing? I mean I'm coming from shooting USPSA/IDPA/Steel Challenge I just don't get this one? I mean the steel is 1/2 or 3/8 I would assume AR500 so?