You can still dream, just not about a Barrett. Swiss made Nemisis repeaters are available, as well as some Steyr rifles. The jury is still out as to Accuracy International's
.50 offerings. There are a smattering of single shot bolt removals around. The problem is not so much the rifle, but feeding them. Because of the export ban, less exspensive ammo is very difficult to get here, making these rifle very, very, exspensive to feed. Even realoading components are big coin. So if you want to shoot .50's, prepare to get out your wallet, and prepare to leave it out.
R.