Plinking round best suited is the UNIVERSAL load developed by C.E. Harris: a 180 CAST bullet ahead of 13 or 14 grains of Red Dot shotgun powder.
Develops about 1800 ft/sec and generally 2 MOA or under out to about 200.
Buffdog uses this load for gopher-sniping out to 300. The gophers don't complain.
Dime a shot, too, and pressures are in the basement.
DO have fun!
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