Hi Jeff,
There are lots of versions of the .400/360 NE.
First there was a .400/.360BPE round which I have no data about.
The Westley variant actually uses a .358 to .360 bullet.
It is the 41 grs cordite 314 grs bullet load.
It is actually very close to the .400/.350NE loading which has .358 bullets 43 grs cordite and 310grs bullet.
The others normally use a nominal .366 bullet.
I just purchased a Fraser gun which has .371 grooves on both barrels and is proved for 43 grs cordite and 310 grs bullets. That's a weird one all right.
So there is a lot of variation here.
Another parameter is the rim thickness which also varies between the different versions...
At the end, make sure you slug the bore, especially if this is a Westley gun!
Brass can easily be formed from 9.3x74r cut to length...
Best regards,
WC-
