The biggest thing with the certification of higher velocities for sniper rifles is mating up proven ability (even under stress or adrenaline) to properly judge distances, mainly to the point of safe minimum engagement distances in proportion to the higher powered guns. Examples, at 450fps I wouldn't shoot anyone within 100ft, 500fps 130ft, 550fps 150ft, etc. And, all year I've been running what I've found is a sweet spot for my M24 (in it's current configuration), a hair under 400fps, gives me consistant accuracy and allows me to use the rifle in built up area games where AEGs are capped at 350fps..............my running 400fps bolt action also gives me the ability to anyone at any distance, within reason that is. I'd shoot someone at 80ft no problem, but I'd focus on shooting a piece of gear to prevent injury from my 0.36g BBs.
Hope that clears up stuff better for you. I don't have any certifications as tags on my account, I really don't see the point of it for myself since everyone knows of me anyways. Just unsure how many know I've been given certified instructor status as well as Level 3 certification. Meh............ hehehe