Check it out:

Comparing double rifles by Holland & Holland & James Purdey…

I forget the caliber of the Royal. It's a BP gun and you can see how much bigger the bullet is.

OWD

I didn't see the chambering of the H & H listed. 450 X 3 1/4 maybe? Doesn't look like my 500 BPE.

Yeah - that sounds right. I'm not certain.

How is your .500 different?

OWD

What is the weight of each gun? The weight of the barrels? Is the Purdey heavier or lighter than other similar 303 rifles and is the Holland heavier or lighter than comparable 500bpes?

PM,

Sorry, but no idea.

OWD