A rim thickness gauge will come in handy trying to do the 50 yard challenge.
I want to do it without going broke buying High end ammo. I Have some:
SK Plus
Remington Target
S&W Standard Velocity
Ruko Target
Eely Club
CCI Standard Velocity
Old White Box Winchester T-22 (supposed to be decent)
New Grey Box Winchester T-22 ( Crap )
Federal Gold Medal Match
A-1 Standard Velocity. Older target ammo in a grey, and blue box.
I also have Blaser, American Eagle, CCI Stingers, CCI Mini Mags, Winchester Experts & Dynapoints.
But I don't expect 5 five shot 1/2 inch groups on the same target with high velocity ammo.
I hope to do the Challenge with my CZ 452 Varmint, and my Ruger 10/22 with a KIDD match barrel.