Originally Posted by
CamoCop
what's the difference between needing certain weight (grains) to prevent dry firing your bow and needing the proper spine stifness for accuracy and true arrow flight? i guess what i'm asking is...i shoot Beman Realtree MFX 340's at 10.4 grains per inch. i was told this is about as light as you can go for my bow (76# /w 30" arrows) without dry firing it. so how could i use the same "340" arrows that are that much lighter (2.2 grains per inch) without damaging my bow? correct me if i'm wrong but isn't "340" something to do with the spine and not grains per inch. if this is true than you aren't really gaining anything if you still have to shoot arrows at certain weights. your just shooting stiffer arrows, not "lighter" arrows.
The 340 is the spine, you get that off of a chart that the manufacturers put out. The minimum amount of weight you should shoot is 5 grains per pound of draw weight, this is how they determine IBO speed. Most people agree that you should shoot an arrow that weighs 6 grains per pound. The absolute minimum weight arrow out of a 76# bow is 5 x 76= 380 grains. At this weight the bow would become pretty noisy so I believe also that 6 grains is a better starting point, 6 x 76 = 456 grain arrow. The ones that your using now weigh 10.4 x 30 = 312 grains. Then add 100 grains for the tip and about another 35 grains for inserts, nocks and fletchings for a total of about 447 grains. I'd stay right where you are and not go any lighter.