After IBO came up with their 5 grains of arrow weight per pound of draw length and 80 pounds max draw weight rule, people started seeing how much speed they could get out of their bows and still be ' legal.' The manufacturers picked up on it, decided most people would be shooting 70 pounds instead of 80, pulled the 30" draw length off the AMO rating and bingo! the ' IBO rating' was born. IBO never had anything to do with setting up any kind of rating.

All IBO did was write a rule for their tournaments to keep idjits from hurting themselves and others by too light of an arrow off too much bow. Lots of people were hurt in the early days by exploding bows, boneheads shooting 300 grain arrows at 90 pounds draw - nothing more than a barely restrained dry fire. It was entirely a safety issue for IBO. Nothing more, nothing less.

The ' IBO rating' has never been officially adopted by the industry, but they sure sell a lot of bows by advertising it. They even adopted a light arrow version of the AMO spec in 1999, a 360 grain arrow at 60 pounds and 30" draw but they have never once used it in their advertising. Very few people know the light arrow AMO rating even exists.

6 grains per pound was the industry standard for a safe arrow weight until shooters demanded bows that would handle 5 grains per pound and not rattle when they shook them after a few tournaments.

Anyway...

crissmand, whether you get between AMO and IBO rated speed with your bow depends on how long your draw length is. IF your draw length is 30" or over, then you can safely bet you' re in there somewhere. If you' re drawing 28-29" you might be. If you draw less than 28" , you might very well NOT be.

Rangeball, grab another cup of coffee! Standard AMO rating - 540 gn arrow, 60 pounds, 30" draw. Light arrow rating - 360 gn arrow, 60 pounds, 30" draw. The AMO ratings are spelled out in specification ASTM 1544-99.