.17 REM vs .17HRM
The ad you're looking at is for .17 REM center fire loaded with 25 gr hollow points. Ammo & Ballistics shows 4040 MV with 25 gr bullet 52,000 cups pressure with a 24 inch barrel. Basically a 222 imp and necked for .17. Introduced 1971, has been around a long time but you don't see many of them unless you shoot prairy clothespins. We're talking .17 HRM with 17 gr at 2550 MV in boxes of 50 ea (nonreloadable).