This comment is a bit late, but I just wanted to add my 2 cents worth.

I have a number of ZKK602 rifles but one in particular has been rebarrelled to .404 Jeffery and, without any modifications to the magazine, it fed about 95% of the time. The problem was that some of the rounds would not rise up quite high enough, at the rear of the magazine, to be picked up by the bolt. As I pushed the bolt forward, it would just skim over the rim of the case. However, it only took a little careful polishing of the feed rails and it now feeds 100%.

When I had this rifle built I was debating between the .416 Rigby and the .404 Jeffery and I went with the Jeffery because:

1. I can fit an extra .404 in the magazine than I could a .416 Rigby (5 rounds fit in my .404 as opposed to 4 rounds of .416 Rigby), and

2. I suspected that getting the .404 to feed would be a whole lot easier than getting the .416 Rigby to feed - and it sounds like I was right.

I am amazed that a factory CZ550 in .404 Jeffery has feed problems when it seems like an easy thing for the factory to fix, especially at the cost of one of these rifles! In fact, it is criminal that any factory rifle can be shipped with feeding problems!

p.s. I am also curious as to why I can fit more rounds into my ZKK602 than can be fitted into the CZ550s. My .375H&H holds six (6) rounds in the magazine!