HiBen,
I thought you maybe interested in Woodleighs reply to my question of whether THEY had a preferance between 410 gr SN and 450gr SN for Northern Territory buffalo. Their reply appears below....

Unless you are a heavy bullet fan, there is no need for the 450gr.
The heavier bullet does increase penetration, but also kicks more.
It is really a personal choice. I would be happy with either bullet.
It is best to use a SN for first shot, and solids for follow up shots if necessary.
Regards,
Geoff McDonald.

Woodleigh Bullets
PO Box 15, Murrabit, VIC, 3579, Australia
Ph. 61 3 5457 2226
Fax. 61 3 5457 2339
Email zedfield@iinet.net.au
Web www.woodleighbullets.com.au

Have got some 450 gr on order.....just to see how they go. Do you have any load data in 416 Rigby?
Hope this helps.