RUIN,
I use JSB Match Light (Green tin), JSB Match Medium (orange tin), RWS R10 Pistol, RWS Meisterkuglen Pistol & Qiang Yuan Match.
All shoot very well in my MP-46M.
Given the main limitation in aiming is my eyes, when I shoot the MP-46M bench-rested at 10m, the above pellets give about the same size of groups (subject to the usual variability of group sizes) - round about 10 - 12 mm.
Have fun & a good Sunday,
Best regards
Russ