On the suggestion of Mr Gain here we go. . .
As we all keep reading .17HMR ammo quality has fallen over the years with split cases and in some instances squib rounds which has resulted in serious damage to some rifles. Having been shooting the .17HMR for eleven years I've experienced it. It seems the finger of this decline is pointed again and again at CCI who apparently make .17HMR ammo for all brands. Well they used to until Winchester after, we assume, being implicated with inferior ammo moved away from CCI and now make their own .17HMR ammo. I am lead to understand this happened over the last two years sometime, not quite sure when.
Winchester claim . . .
"Stronger shoulder for improved case integrity"
"More efficient powder for reduced pressures and consistent velocities"
"Stronger rim maximizes head strength, and proprietary priming mix results in consistent ignition"
Personally along with others I know who use this ammunition have found the above to be true and as yet after many thousand rounds have had no problem with squib rounds although a few cracked cases still occur after firing. Velocities over the chronograph seem in line with their advertised 2,550 ft/sec and seem relatively consistent. With other brands I could get velocity ranges of up to 200 ft/sec or more!
Accuracy wise from CZ 452 Varmint, 530mm / 20 3/4" barrel (moderated) I still get 1/2" 5 shot groups at 100 yards. I think that is perfectly acceptable.
It's worth pointing out that there is still some old CCI made Winchester ammo floating about and although I can't be sure of the serial numbers the new Winchester .17HMR ammo to look for has the following serial numbers and this is the stuff that seems to be working for us.
Varmint HV - CS17HMR1 - V-max - 17gr
Super-X - CX17HMR1 - Jacketed Hollow Point - 20gr
The big question is if you have used Winchester 17 or 20 grain ammo what have your experiences been?
You never know we might have found a reliable brand!?
Following page taken from the Winchester brochure. . .
Picture shows a slab of 250 rounds but they come in the red boxes of 50