Online reviews say that the size is inconvenient but it's extremely accurate. It's 6'8 long and weighs between 59 and 130 pounds. They sell a bolt-action 20MM rifle using 3 round magazines for $11,900 or $16,200 for accessories and a suppressor. 50 BMG and is used in miniguns and anti-material rifles. This ammo is about four times as powerful as. However, a company named Anzio Ironworks makes several rifles that use the (larger) 20x102 Vulcan round. The largest practically available caliber is.