They probably came to public attention at Waco where the Davidians were accused of using them to hold government helicopters at bay. Since that time, a number of people have acquired them as the ultimate long range shooter. Most are single shots, like the Maadi-Griffins, distributed by Mr. Steward. There are also some semi-automatic models. Almost all people believe that these rifles are monstrous.
Surplus bullets are available in armor piercing, incendiary and tracer configurations.
Many are almost five feet long. They weigh up to 30 pounds and are best fired from a tripod. The muzzle blast and recoil scare many away. The cost of shooting them is almost as bad. You can expect to pay a couple of dollars per shot even with cheap surplus ammunition.