Hey George! You might be on to something there!
     

why are people comparing what a bullet does in sand and what an arrow does?
the arrow will out penetrate the bullet because of momentum, the arrow weighs a lot compare to a bullet. yes the bullet has a lot more "kinetic energy" but that just goes to show you how bad kinetic energy is in relation to predicting penetration. momentum is how you predict penetration.

why would a 600 grain broad head with a string attached to it have anything to do with how it penetrates. tie a 20 foot string to one of your arrows and shoot it. it still fly's and it still penetrates. no difference. if you could somehow propel the broadhead 180fps it would out penetrate any cedar shaft of the same weight.

if you want to talk about bullets a bullet doesn't need any weighted shaft behind it to penetrate. it is basically a light broadhead flying really fast.

indians have been killing animals with stone points for thousands of years. you should be fine with any "normal" foc, to steal a line efoc is just a higher degree of better.

"if you want to talk about bullets a bullet doesn't need any weighted shaft behind it to penetrate. it is basically a light broadhead flying really fast."

Well, I guess that's why I compared it eh?  

I must say that these front of center discussions are interesting for old pharts like me.  They actually make me try new things (shhhuuuudddder).  I had an opportunity to buy some aluminum arrows at a very cheap price...$19.95 for the dozen, already fletched with 5" feathers.  They are 2314 which would normally be too stiff for my bows at a 28 1/2" arrow length.

So....I bought some 125 grain steel broadhead adaptors and mounted my old Bear Razorheads on them.  The total arrow weight is about 565'ish and they fly great....out of both my recurve (52#) and longbow (57#).  I wouldn't call these extreme front of center, but they are more than I usually shoot and I certainly can't complain about the result.

I'll post some more about them when I see how well they do on game.  I have no doubt they will be very good.