The 22-3000 used the original 25/20 case, the long, non-bottle necked black powder case - not the .25/20 Winchester. The .22-3000 was the first .22 round (prob. .223") to break 3,000fps for groundhog shooting. At the time, the .22 Hornet was running in the 2,640fps range, up from the previous 2,350fps it started with - and still loaded to in Europe for some of the early combination guns or ctg. conversion tubes for shotguns.

The 8.15x46R is an old Austrian/German match ctg. soemtimes used today in Raton NM for the cast bullet Silhouette competitions, when used, it is mostlty in the Adyt Single shot rifles.
IIRC.