275 #2 rigby flanged vs. 7 mm H&H flanged

What are the differences between these 2 cartridges?Only neck lenght?

Thanks

I believe the rim is thicker on the .275 No 2.

I read that the neck lenght is different too.
I have the 7 mm H&H but not the 275,could you post a picture of the two side by side to note the differences?
Thank you

Pivi,
I don’t have either cartridge in my collection. :(

In Hoyem’s Vol III British Sporting Rifle Cartridges, he states that the rim is thicker on the .275 No2 as it was based on the .375 Flanged.

The rim on the .275 No 2 is wider & thicker than the 7mm H&H. This is because the .275 No 2 is necked down from the .375 x 2.5 in Express while the 7mm H&H is a necked up .240 H&H or a necked down .375/.303. The neck of the 7mm H&H is also slightly longer.
Watch out for future editions of the IAA Journal - I have written detailed articles on these two cartridges.
I do not have a photo of these ctgs together for comparison - only individual photos at different scales.

OK thanks.

John P-C,I found the 475 NE we had talking about