CZ magazines - I have had a 452 for over 20 years and when I purchased spare mags for it I purchased the polymer mags, I prefer them over the metal mags, IMO they feed smoother than the metal mags do. Wear on them has not been an issue and neither has breakage.
Federal UM ammo - from my memory the dimple design was copied from the Russiam match ammo that they were kicking our butts with in international matches. Federal took the dimple design and incorporated into their ammo and developed the UM for the US teams., IIRC they did quite well with it.
I do recall reading an interview with a Federal manager when they quit making it and when he was asked why the reply was that the market was so small and manufacturing it was so costly that they were losing money on it - just too specialized of a market at the time.
Tightening groups with the CZ 457 American - the American has rather sharp (grabby) checkering on the bottom of the fore-end which catches on the seams or the front bag (Protektor) and on other frontbags, depending on the type of bag material it will catch on the material itself, which is bad for accuracy since the recoil is already starting to occur before the bullet leaves the barrel.
I cut group size and got rid of flyers by using a folded micro-fiber cloth laid on top of the front bag. It has been too windy the last few days to do any testing but when the wind dies down in a few days I will establish a baseline for the micro-fiber and then try a folded towel on the front bag to see hoif there is a'y improvement over the micro-fiber.
At this time it looks like it wants to shoot 1/2" ten shot groups at 50 yards but the only ammo I have tried is CCI S/V and TAC 22 (red box), that seems to be about the limit of those ammos accuracy in any of my 22's.
Once I am satisfied that I have a valid baseline with those two I will try some midgrade match ammo. Although ten shot 1/2" groups at 50 yards from a sporter is nothing to be sneezed at, the only other 22 LR sporters I have had that would do that were my Cooper 57, Tikka T1X, and Anschutz 1710.
drover
