I picked mine up last week and went through it since I haven't had time to take it to the range yet... and I just happened to have ~390 rounds of wallyworld fed bulk pack sitting around.
The problem that the P22 has with Fed BP is the shape of the bullet, how soft the lead is, and the *very* sharp machine line at the mouth of the chamber. The angle and smoothness of the feed ramp is alright, but there's a little relief to accomodate the cartridge rim, and that edge is like a razor. I took 1/16" slivers out of every bullet I manually chambered before I figured out what was going on.
So, I took my warranty into my own hands and did a very tiny relief. .22LR doesn't need 100% case support since it's not reloadable, 99.9% should do... but don't take my word as gospel, I'm just a yahoo with a set of needle files and spare time.
I can, however, now manually chamber a full clip of fed bulk pack without shaving chunks off the bullets or getting any stuck at the mouth of the chamber.
I can't get to the range to try it.... Actually, what I can't wait to do is take the barrel to the local college's CAD/CAM shop and see if I can have a barrel for .17 Mach 2 made