I used to use the dimpled base Federal. Mine was 900B. Really good stuff, & they had one, maybe 2 more of the dimpled base that were even better. The best supposedly was loaded by hand & put together for the US Olympic team.
Yeah, just looked it up. UM1, the stuff made to try & beat the Russians & was copied off a Russian priming process, or so the story goes.
Um2, Um1 seconds used for practice & then the 900.
If 10X is 20 bucks a box now, what would a good supply of UM1 be worth?