I have just been introduced to this calibre by Ed Hubel and RNS, which for those who might not be familiar with it, is a 460 Wby taken out to a straight case which equates to 550 calibre. I think Geoff McDonald (Woodleigh) had something similar but he went up to about 54 calibre, so his case would have a slightly greater taper.

RNS who has got things organised amd moving has this whole thing set up so it is all straight forward and easy....and a low price.

My calculations show that if it was loaded to the same pressure as 460 doing 2500 f/s with 500 grainers then the 550 would do 2250 f/s with 750 grainers. If the 585 Nyati has decent brass it would go faster but most who have posted up details on their 585 Nyatis seem to indicate that 2200 f/s with 750s is the end of the road due to recoil.

550 calibre should also allow the use of 900 grains bullets and they shoud do 2050 with the pressure used in a 460 to do 2500 f/s with 500 grainers.

So in short, for practical purposes it can deliver the maximum power that you can use from a normal rifle and at the same time would allow bullets up to 800 or 900 grains to be used. Yet at the same time there are no brass problems such as soft cases or poorly dimensioned cases and obviously conversion of a CZ 416 Rigby or a Weatherby Mark V is as easy as can bee. In addition, being 550 it should and will be must better suited to lighter bullets at the 600 grain end of the spectrum.

I just need to check use of 50 cal plus at our rifle range, which I am 99% sure is OK with the only problem being the 50 BMG and then my cheque makes its trip across the ocean.

Mike