I also opted for the .500 Jeffrey over the .505 Gibbs. I've had the rifle for 3 years and use it extensively and have never had a problem with feeding or with anything else....it's certainly the most effective calibre I've used on DG.

I'm not a gunsmith, but hopefully some will post their opinions, but I find it hard to believe that any particular calibre round is prone to jamming.......surely that's the fault of a badly designed action?