Hey 9Threefifty, I tried what you said:

1) I tried this 10 times with a full magazine doing it for each round:

Point the rifle at the ground. That is, stand the butt up, muzzle down.

S-L-O-W-L-Y work the bolt and feed a round from the magazine as you juggle the gun a bit.

Repeat a few times.

It fed flawlessly, my rifle has been worked over by both the CZ custom shop and AHR though ... I don't claim all the CZ 550 big bores will do this.

2) My gun will close over a round fed directly in the chamber. I tried it 10 times both by pushing the round in the chamber with my fingers and then closing the bolt over it, as well as just laying the round part of the way in and just on top of the magazine but not clicking it in. In all cases it fed. In all cases it did not close over the bolt as smoothly as when fed from the magazine. On my Rem 700 270 I routinely feed cartridges into the chamber by hand and neck size only. For the 375 H&H I intent to only feed from the magazine. If 5 shots won't do it I need to learn how to shoot ...

Chuck