For those interested I have read a lot about 220 grain hard cast bullets not shooting well out of G20s. I don't have personal knowledge; but, I have read it enough such that I have been carrying 200 grain hard cast and they shoot great in my G20 and G29, even with the stock 17 lb spring if I forget to change it out. From what I have read it is usually an accuracy problem.
I've read that years ago, but it was always in reference to a particular manufacturer's ammo (Double Tap). Those issues all seemed to be caused by undersized bullets and weren't really anything to do with the weight; at that time some people were reporting pulled bullet diameters as small as.397-.398", when they should have been .401"-.402". That's definitely enough undersized to cause accuracy problems. That was 10-12 years ago though; I have no idea if Double Tap has fixed that by now, but would guess they probably have.
I've cast and loaded several different 220gr bullets over the years, even one design I made up myself, and never had accuracy issues with any of them in Glocks or other pistols.
