Thanks Sarg, good to get confirmation.

The 9.3x74R cases I have measured were from 79gr to 82gr H2O depending on the make. But the 9.3x74R case is 2.92" long compared to 2.75" long for the 400/360's and 400/350.

Barnes gives the following measurements for each of these cases as:

400/360 WR = .437" at the shoulder

all the other 400/360 variants = .417" at the shoulder

400/350 Rigby and 350 Rigby No2 = .415" at the shoulder

9.3x74R = .414" at the shoulder (Pierre van der Walt shows .409" shoulder)

So the 400/360 WR is the only one with enough shoulder to head space on once the rim is turned off.

4seventy the 400/360 WR shoulder gives a .062" step at the shoulder to head space against which is the same as the 9.3x62 at .060" according to the CIP drawing in van der Walts book.

Sarg are you able to measure one of your cases for shoulder dia, neck dia, neck length and overall case length to comfirm? Looks like it could be a fairly potent medium bore going by case capacity.