i have fired thousands of rounds of this ammunition in dozens or .17hmr guns. I fell in love with this fast shooting low trajectory round shooting belding ground squirrels out west. It absolutely devastates on impact. I have had no issues with zeroing the weapons. Lately I have noticed that in two different lots purchased two years ago I am having some case cracks around the neck in a Savage and Browning that I own. I have inspected the rifles and they are fine, I chalk this up to the brass casting in some manner. Other then this minor issue, I can tell you that this is one of the better small game/plinking/teaching a kid to shoot ammo and caliber available. I have somewhere close to 12k rounds and have not had any misfires that one gentlemen mentioned.