There are many things that can effect chronograph readings. Light is the biggest one. The most consistently true readings are done indoors using in infrared light kit that are designed for the pro chronograph.
other things that can cause variable speed readings, or incorrect readings is a shinny field tip, the angle the arrow passes through the chronograph, inconsistent draw lengths, or longer than normal draw lengths, and the release.
A target archer that holds at full draw is going to get much lower readings than a flight shooter or snap shooter will..... every time. That's a fact.
The most accurate measurements to test the bow are taken using a shooting machine after accurately weighing the arrows and using a precise digital scale to measure draw weight to the same draw used on the machine.
This is where you see a lot of what seem to be really high numbers posted... The bow is marked 50@28" when in fact the bow is really 52.5 pounds @ 28", then it's being over drawn to 28.5" instead of 28". It's quite conman to over draw a bit when testing by hand.
Even using precise digital scales and a shooting machine it can vary from one test to the next, and It can vary a lot from machine testing to shooting with fingers depending on the release.
With a machine you are testing the bow itself for use in comparing efficiency ratings from one bow to the next. shooting by hand tells you what your hunting weight arrows are doing under realistic conditions.....
I've got long bows I've tested at 237 FPS using light weight shafts.... but it doesn't really matter if you can't use those arrows in your bow without blowing the bow up. 9-10 gpp is the normal range.
02 cents worth....
Topic: Arrow speed (Read 1029 times)
