arrow & broad head speed/weight
 

im shooting an 2010 Martin MOab with a 26 inch draw and 62 lbs draw weight. what Grain per inch arrows should i be shooting. and what grain broad head? i was looking at some 9.0gpi arrows or some 7.4 gpi arrows. and once i decide that im not sure what grain broad head. 100 or 85. i just want something thats going to shoot with enough speed but also no be to light either. any advice would help thanks.

OK, all I did was pick Easton's shaft selector to get the spine needed. Looks like a 500 spine. The went to Gold Tip's site to "Build an Arrow". Using 26" Expedition Hunter shafts (3555/7.4 gpi), 2" vanes, Microlite nock, insert and 100 gr point you'd end up with a shaft weighing about 328 grains with an FOC a little over 13%.

If you want to use a 125 gr head then a 400 spine (GT 5575) would work OK. The 500 might be just a tad too limber.

Some would say this is too light for hunting, but assuming it's deer then this would be a nice compromise between speed and penetration capability.

A 9.0 gpi shaft will work, too. You won't get as much speed and kinetic energy will be about the same, but the heavier arrow will carry more momentum down range. The choice is yours as either arrow would be enough for deer sized game. Also considerr the distances you'd be shooting for hunting. If it's the normal 25 yards or less then trajectory still won't be much of a concern. If you live out west where longer shots are more normal then maybe the lighter arrow, with flatter trajectory, might suit you better.

Don't confuse arrow weight with spine. For a hunting setup almost any arrow made will be heavy enough. Proper spine will ensure good flight characteristics for best penetration assuming you tune the bow/arrow combination to achieve good flight.