+1 on the Hornaday ammo. I shot a man's 17 hmr CZ 452 twice at my range and that was enough for me. Dead nuts accurate and shot like a laser @ 100 yards. Took a couple of months and I finally found a gorgeous example of a CZ 452. Stuck a Nikon rimfire BDC scope on it that I had laying around. No problem putting 5 shots in a 1" circle at 100 yards with Hornaday 17gr. off a bag rest if the wind co-operates.. Back to the ammo. I've shot Hornaday 17gr. & 20gr. & Winchester 17 gr. The Hornaday 17 is scary accurate, but a breeze will push your groups if you don't account for it. The 20 gr. is good, but has more drop at 100 yards. The Winchester, I was not impressed with. I could not get near as tight groups at 50 or 100 yards. But it is still good for minute of bunny rabbit at 100 yards. I have not tried any CCI yet as I have not found any local. Rimfire Central is a good place to learn about 17hmr. Very friendly and informative.