Re: m110 info
Issued M110 in country? That being said, everywhere i've been there is at least a 25m zero range for test fire of MG's , zeroing of M4/M16, or CQB markmanship training. If there is no way you can get to a longer range nearby, I would talk to your PSG, PL, or CO about working up an operational needs statement to order and ship a chronograph to you.Muzzle velocity and effects with temp are pretty well documented with issued ammo and weapons.
Knights Armament Lists: 2517 fps with M118LR. If you enter that into the ballistics program at default altitude, temp, and pressure, it should be able to provide you with a baseline trajectory under different conditions.
Best of luck and shoot straight!