You'll have to zero it at the field then. Fire off some rounds and adjust the hop up to make them fly as far as possible before flying upwards, then tweak it back a bit to let them fly as far as possible then drop. Once you have that set, pick a target about 100ft away and dial in your scope to where the BBs hit where you are aiming. Then you should be good, but know that you will have to compensate for elevation and windage by eye when playing. And I wouldn't recommend anything lower than .28g BBs. Heavier is always better, as long as you learn how your gun shoots and how to compensate to get rounds on target.
BTW, if you don't use hop up, say you have it set at full off, then your BBs will roll out the end of the barrel once loaded. The hop up nub keeps them in place until you shoot. If you dial it in for minimum setting, even 0.20g BBs will drop within 40-60ft. You NEED to set your hop up and use it, there is no "Don't use it because I don't want them flying upwards" in this, otherwise you'll frustrate yourself into thinking others have upgraded guns because they can hit you from 150ft away and you can't even get past the 60ft mark. Learn the gun, learn the ballistics of the BBs you are using, learn to shoot and move well, and pay attention to the BBs behavior during flight.
You bought a bolt action sniper rifle for a reason, time to upgrade and tune the player to let the rifle do what it's designed to do.