Well I doubt that, a ping of 1500 means a dealy of 1,5 seconds. That means between the server state and your displayed state is a differenc of 1,5 seconds. No mathematical prediction can compensate that. I've read articles about networking programming where they state that the maximum ping a FPS game should take into account is 70.
Lythandros is correct (and old).
Actually, I played Counter-strike beta 5.2 in 1999 before client-side hit detection was INVENTED.
I played with a 56k moden and my ping was 400ms.
The only way you could hit anyone moving orthogonally (perpendicular) to your direction of aim, was to have a P90 because it had 50 bullets and you had to lead a target a good 4 meters in front of them in the direction they were traveling.
If you were shooting at a stationary target, and were dead-on with your aim, and you fired, it would take 400ms for your hit to register and you to see blood or a hit animation.
The same would be true for 1500ms ping.
It would take 1.5seconds for a hit to register after the moment you click.
Believe me, I yelled plenty of expletives because of this phenomenon back in the good ole days. Lag was king in those days. Usually starting with fuh and ending in king-lag!