if you necked down a 50 AE to a 22 or 25 caliber and sent it out a 4" barrel, what kind of velocity might one get? Maybe out of sabots?
Back when Dick Casull was first marketing his now-popular round, there was also a companion piece. A Ruger #3 single-shot carbine. There was also a lesser-known 22-454 Casull. The 454 Casull case necked down to .334" and it delivered a 52 grain bullet out of the 20" barrel at just over 4,000 fps. $300. The price kind to tells you how long ago that was.