Have 3 of my own 20 Prac barrels, 2 others familiar to me, they ALL like to jump .020"ish, pretty much any powder that works good in 223 works good in 20 Prac, and for a cheap, short range plinking or small varmint round don't overlook the Midway Dogtown/Midsouth VNE 34g flat base HP, they will shoot surprisingly well for 9 cents a piece vs. 20+ cents per for everything else.