Yes, I too am assuming its the 5/5 round mag. Yes the 5/20 is much easier.
What I did with my 5/5 mag was polish the areas on the mag where it contacts the mag well. You can see the areas it contacts, cause the parkerizing wears away. I polished these areas with some 2000 grit paper. Made it better, but 20 rounds are still the way.