We talk about bullet construction, penetration and expansion here frequently. I have always wondered what makers strive for in the way of optimal expansion in a Tough, Dangerous Game soft point. If it expands too much, it will likely limit penetration. Just for example, what would be the optimal expansion for a 400 grain .416 softpoint(lead core) on a frontal chest shot on Buff? Would 60 caliber be about perfect with good penetration ? if the same bullet expanded to 90 caliber, is that past its design ratio? I realize there are a lot of variables with this, but I am curious what bullet designers would consider as min/max.

We "bullet designers" like to see no more than 100% expansion, prefer 50-100% expansion, so yes, 90-caliber from a 41-caliber is too much.
Sounds like a Woodleigh Weldcore soft driven too fast.

Of course some of us also like to see 0% expansion and keep the weight loss of the NonCon "Hexploding" bullets down to no more than 35% weight lost to petal production.