Most persons probably have no clue of the legendary BMG 50 caliber in comparison to the other common loads. Here's a good comparison by pics.
"The .50 BMG is a very large round and as such, requires heavy weapons and supporting equipment in order to fire safely and accurately. Civilians can purchase these rounds in factory loads ranging from 650 to 750 grain.
In regards to ballistics, the .50 BMG has a bigger, heavier bullet that delivers a reliable killing shot at ranges up to 3300 yards and take down medium-sized game at these incredible ranges. The bullet hangs in the air for a full seven seconds at this range and has a significant drop in elevation."
"These heavy sniper rifles were originally intended as anti materiel weapons for stand-off attack against high-value targets, such as radar control vans, missiles, parked aircraft, and bulk fuel and ammunition storage sites….It is their ability to shoot through all but the heaviest shielding material, and their devastating effects, that make them valuable psychological weapons."