RE: 75 grain broadhead
The arrow would have to be very light to get good FOC. Even if they are efficient that does not mean you try to go as light as possible and it's still all good. Without the weight behind it speed means nothing. Even if you spine properly and have correct FOC it's still a light arrow out of a bow that produces low KE.I'd rather see a man, woman, or teenwith a 45-50 lb bow shoot a 500 gr arrow 220 FPS then a 320 gr arrow 270 fps.
I think that is something a lot of people are overlooking. When we had the older slower bows (in theearly to mid 80's)we also shot heavier arrows. I used to shoot a 30" 2219 arrow with a 135 gr tip (about 580 gr)at 220 fps and that was considered good. Then the 75 gr and such tips came from 3-D shooters who wanted to shoot flatter so that if they misjudged by a little they were fine. Then, the BH manufacturers started to pander to that crowd and the 75 gr BH was born.
The 1 point that I agreeon many of the guys that preach heavy FOC arrowsis that for people with low DW's they should be using a heavy tip wit ha stiff arrow.