I have some big Hard Cast .44 Magnum I'm hopefully testing tomorrow. It's interesting in this article the reference made to Buffalo Bore and "too large" of Meplat for penetration. Now I'm heading over to find where on Buffalo Bore's site they found that.
http://www.lasc.us/fryxell44overweight.htm
The article may be referring to meplat diameter in relation to bullet diameter. A 70% meplat is generally accepted as the optimum combination of penetration and damage. Some claim that larger meplats don't penetrate as straight, and may even tumble.
I searched all their ammo info and the tech articles and couldn't find this info. Maybe it was long ago Buffalo Bore wrote that somewhere.
It is clear that at some point a metplat passes an optimum or we would all shoot full wadcutters instead of having any taper or rounding to the nose profile, especially in revolvers where loading issues are less of a consideration.
I am a fan of a 75% metplat. This gives a 10mm (.401") a metplat of .300". Nice and tidy, feeds well in my auto's and punches a nice round hole. In a 200-210 grain bullet design, there is still plenty of case capacity left to push it fast too.
In 44 this would give a .320" metplat for my optimum design. The 44 magnum, having such a large case, is pretty easy to get well into the 300's in weight without limiting case capacity at all.