I've tested 700 grain handloads (using Ranger Rick's 700 grain bullet and it looks like Underwood is using one of their molds) and they were an abject failure. Too much of a good thing. In wet pack they wouldn't track straight.
I wonder how they work in animal tissue? This is interesting. The owner of
http://www.ballisticsupply.net/Default.aspx?tabid=252105said the same thing about his product.