You're allowed to highjack your own thread!
But isn't it good to finally shed some light on why the newer CZ's seem to perform with either heavier bullets or charges?

I'd seriously look at the Ruger #1 in 500 NE, especially if you ever think you might shoot Blackpowder Express.

Also, it might be good if you spoke to the fellow shooter in Bris with the CZ 505 Gibbs, ask him if you could possibly shoot a whole Group 3 match with his 505, at least then you will know after the 8 shots if it will/might suit you. Also I hold bi-monthly BGR shoots at the complex at Millmerran, you would be most welcome to come out and fire my 500 Jeffery to see what you think of it, if you like.
And lastly, the QLD BGR titles are in Gladstone this coming October (I think) I'll bet that if you fronted up you'd get at least a few Group 3 rifles thrust into your hands and told to have a shot. I'm certain there will be a few Ruger #1's in 500 NE there, also a 500 A-Square or two from up north.
Come and have a shot and see what you think.

Regards,
David.