I have 2 CZ 457's. One is the standard varmint and the other is the Varmint MTR. Both love the SK Standard Plus, Norma Tac-22, and RWS Rifle Match. I get groups with all of these just like you got with your first and last groups. I'm having a blast shooting my CZ's. Looks like you are too. Good shooting....
Those are damn nice rifles. Yours looks like it's all over the place, and very inconsistent. I'm wondering if you are having a parallax issue with that Leupold? Hopefully it/you settle down.
I suspect the rifle will settle in and your bench-rested groupings will tighten up appreciably with more rounds of the SK down the barrel. I've had my CZ 457 American since this past March, and first tried the CCI Standard Velocity (very good groupings for the money), then Eley Match (slightly tighter but certainly not the performance improvement I'd expected), and mostly recently, SK Standard Velocity. The SK's groupings were instantly tighter and the improvement was very obvious and immediately apparent - a massive difference from the Eley Match. My last grouping of 5 rounds at 50 yards bench-rested with the SK ammo were a very tight triangle (ie almost all rounds in the same bullet hole). That's with a Leupold VX Freedom 3-9x40mm scope (not the rimfire model).
I’m trying out a couple different Leupold scopes and it should help when I choose one and settle into a more consistent eye position as well. Thanks for the info. The cz is so fun to shoot!
My groups are getting tighter and less erratic since I added a Timney trigger and set it at 1.25 lbs. I will post new results soon. My average is .4” -.6” with some .25”- .35” each time I shoot.
