Close in hunting, I used 11.5 -13 gpp. Killed after with a near 14 gpp. Slow arrow. However, once I internalized the flight of a 9.5-10.5 gpp, I see the advantages. Seems my stumping arrow is reaching out to 25 plus yards, easily hitting the spot. Up close, in the brush of mtns, I could see grain per pound above 10. They do sink deeper in my test. But as I rebuild my shot sequence, and draw gets above 28", I see the arrow speed move up. More speed helps the 450-485 grain arrows hit harder.