My Merkel .500 NE weighs 10lb. 4oz., and is not unmanageable. HOWEVER: I'd not have objected had the rifle weighed more - my .458 bolt gun weighs 10lb. 12oz., and is comfortable to shoot - I'd have happily put up with a weight of 11 1/2 to 12 lbs in the .500, which would, I think, have brought it into the same felt recoil league with the .458. Apparently the average weight of British DRs in .500 NE was around 12 lbs. - the Brits were pretty sensible about making their dangerous game rifles manageable, both in carry and shooting when the time came, and I don't think there is any need to improve on what worked for them, in this case. Lighter-than-standard weight heavy caliber rifles are specialized tools for the experienced shot who both knows what he wants and is willing to make the compromises such a rifle represents. Also, FWIW, it wouldn't have hurt (!) anything had Merkel put a good recoil pad on the .500 NE in the first place. I'll probably do that, eventually, and may experiment with a mercury recoil reducer, though I don't feel there is any good way to increase the overall weight of the rifle without possibly negatively impacting regulation. We'll see.
mhb - Mike