Bruce and bow hunter44 I agree with your points about penetration. From my original post:
For guys out west they need a balance of good weight to maintain momentum and decent speed since shots tend to be longer.
It's a balancing act for some guys to have good weight for penetration, yet not sacrifice too much speed by lobbing logs. For some it is just as bow hunter said, "personal preference" to go lighter or heavier. And when I was referring to lighter arrows I meant in the 450 grain range. My arrows I consider to be very light, but with my short draw and arrow selection that is what I have. I've looked into heavier arrows, but don't want to get away from ACCs.
And as the others have said, yes a heavier arrow will absorb the energy more efficiently and be quieter.
Dang it you guys, now you got me wanting to get heavier arrows.[:@] The wife is not going to like that.