You will have to tell us if you are talking about black powder or center fire.
The maximum range of a .50 BMG catridge (there are others) - with no accuracy, is about 6,000 meters. The maximum EFFECTIVE range (skilled marksman) is about 1/3 of that. Prior answers to this question attributed a range that can only be reached by the main guns on a battleship.
Depends on the load and range.
If you mean a rifle chambered for the .50 BMG cartridge, such as the Barrett M82, the EFFECTIVE range is about 5,900 feet. The rifle weighs about 30 pounds, and sells for about $9,000.
Yes, I can. A Barrett M107 is a .50 caliber sniper rifle.
1500-2000 meters
You will have to specify if it is a muzzle loader or a centerfire.
50 caliber
Yes
Any bullet that has a diameter of one half inch is a .50 caliber bullet. There are different .50 caliber bullets- my Hawken muzzle loading rifle shoots a .50 caliber lead bullet, but different from the .50 Browning Machine Gun (that is also used in the .50 Barret sniper rifle)
how far does a 50 caliber sniper rifle shoot accuratly
Over a mile.
In the States, a 50 caliber rifle can be acquired after filing certain tax stamps. Once the tax stamps are paid and a background check has been cleared, then a 50 caliber rifle can be purchased at some specialty gun stores.