[Carthego delenda est]

You mean like a rifle from Anzio Ironworks?
“Available in 14.5mm, 20mm, and new Anzio 20-50 calibers”

http://www.anzioironworks.com/MAG-FED-20MM-RIFLE.htm

SSK Industries has the 14.5mm JDJ:

“SSK has non Destructive Device exemption for a 14.5 MM (.585″) cartridge. The 14.5 MM JDJ is based on the 50 BMG case. The neck is opened to accept the SSK 1173 grain bullet loaded over 235 grains of 5010 to fire form the case. Other bullets may become available in the near future. In the test rifle 100 yard accuracy hovers between .3 and .5″ with this fireform load. Velocity is chronographed at 26–2700 feet per second with the 1173 grain bullet.”

http://sskindustries.com/14-5mm-jdj/

[from occupied ga]

You mean like a rifle from Anzio Ironworks

That would be good. The real Russian 14.5mm has over twice the energy of the .50 BMG. I'm just guessing that a 14.5 on a .50 cal case would carry about the same energy as a .50. Anzio's 20mm would be even better, but the prices are somewhat steep for me. I've regretted for decades not buying a Solothurn or two when they were relatively available and (relatively) cheap in the early '60s