In centerfire, believe it or not, a Hi-Point, C-9. Of course I probably shot it more than any other single non-rimfire, gun I've ever owned. Didn't matter what kind of ammo I used, Blazer, WWB, Rem-Umc, American Eagle, range reloads...it just shot a nice tight group in the center of the target. I had installed the "ghost ring" sight that came in the box. I don't know how much that mattered, but it didn't hurt. Now, I freely admit that I was only shooting at seven yards, but that was all that was available at the range I used back then.
That gun surprised me. It just chugged along.