May 27th, 2011, 09:01 AM
What does GPI mean?
Im shooting FMJ 11.3 GPI. What does that mean? Is it better to be higher or lower in gpi?
May 27th, 2011, 09:02 AM
grains per inch...just multiply number by length of arrow and you know how heavy it is.
May 27th, 2011, 09:03 AM
GPI = Grains Per Inch. More grains means the arrow weighs more.
PSE Source TT Smackdown Pro, B-Stinger,GT 55/75 Arrows, HHA OL-5519 Muzzy Trocar Broadheads, JBK Strings
May 27th, 2011, 09:04 AM
11.3 grains per inch. Higher or lower in gpi means slower or faster arrow speeds from the same bow. It also means stiffer or weaker spine.
May 27th, 2011, 09:59 AM
GPI has nothing to do with spine being weaker or stiffer. Example, Easton FMJ 340 has a GPI of 11.3 and a Easton Flatline 340 has a GPI of 8.2 .
Originally Posted by deadx
Participating in a gun buy-back program because you think that criminals have too many guns is like having yourself castrated because you think your neighbors have too many kids.
May 27th, 2011, 10:09 AM
Yep! What he said. Has nothing to really do with spine. Just weight.
Originally Posted by jwilson48
May 27th, 2011, 10:35 AM
As a general rule, arrows of the same model, from the same manufacturer, such as Gold Tip, will have a higher GPI with the stiffer spine, and therefore they do weigh more as the spine goes up. That does not neccessarily apply when comparing arrows between different manufacturers or even different model arrows from the same manufaturer.
Shutup and Shoot!
May 27th, 2011, 10:37 AM
Higher GPI arrows will weigh more at the same length. So more energy, less speed, but probably in the end more penetration. FMJ's are getting up there as far as weight goes.