There is a point of dimineshing return but it is wayup there.You could shoot 12 gr/lb and still have a decent increase ke and huge increase in momentum,but a big drop in speed,which is overated in the first place.Actually,it is blown WAY out of proportion.[:-] And I am not reccomending 12 gr/lb,just using it as an example.
True, but now we're just talking about how far in the ground you want the arrow to stick in the dirt after it passes through the deer. IMO, when you hit around the 5.8 gpp mark you've got PLENTY of both worlds. You aren't shooting a terribly light arrow, and you aren't shooting a terribly slow arrow. Take my set up for example. I've been messing w/ 2 different arrows, one weighs 425 gr and the other weighs 400 gr. Not a lot, no, but it's a 5 fps difference in speed, again, not alot, but just using it as an example.
The 425 gr. arrow is flying 282, the 400 flys 287. There is only a 2 ft pound difference in KE, 75 and 73 respectively. If I can't blow right through a deer w/ 73 pounds of KE....I just don't think the 2 extra is gonna help anything.
I guess perhaps it's relative to the set up. If you're shooting low poundage and slow anyway, I guess a heavier arrow would be more advantageous, but in with my particular set up, I'll take the speed.