Lars, one of the problems with big bore bolt action rifles regardless of the type of rim is the large diameter cases, particularly the 500 Jeffery and 505 Gibbs. Unless the left action wall is machined to allow the case to roll further under the rail then that exact scenario will happen all the time. When I got my 505 which was supposed to be ready for use it would do exactly that. If I loaded three rounds in the magazine, fed and fired the first one and then rapidly retracted the bolt the second round would fly out of the magazine at the same time as the ejected round that had been fired. I spoke to Wayne from AHR in the US who has built many CZ550's for big cartridges and he told me it was a common problem and the trick is to machine the action wall on the left side with a ball nose cutter to allow more of the case to roll under the rail. I did this and it solved the problem.

Added to this was the magazine spring which on the 505 are 0.020" thick which is to strong and wants to push the cartridge out. The trick is to replace it with a 0.016" spring which is used on most other models and it totally solved the problem.

Matt.