Hornady necked the .22 LR case down to .17 caliber in 2004 to build a screaming little rimfire varmint round that shoots flat and fast on a rimfire budget-ish footprint. It never caught on quite like the .17 HMR but it earned a devoted following among small-varmint hunters who appreciate its performance. A clever little oddball that deserved more attention. Small fast and underrated.
Loads run around 17 grain in the scarce offerings that remain. A niche rimfire priced above the common calibers in small boxes. The dedicated varmint crowd buys whenever it surfaces because it stocks thin.