Johnny, that is a hard question for me to answer. I've notice what you said and have found that even with (supposely) the same spine between 2 different brands, actual weight of the shafts are different. I noticed with my 52#@28, I can get good flight out of GT5575 black shafts and out of the wolverine 5060(walmart) black shaft. both group with themselves 4-6" apart and both weigh different. but they are suppose to be the same spine.

maybe a little more research on the manufacturer's website for their spine chart and compare with other maker's  may help match them up.

have you tried a 500 beman or easton shaft?