how much of an over draw are you shooting? 30 inch draw with 27 inch arrows dont sound right. if you are shooting 57# then you can drop your arrow weight down to 300grains and that will help you out alot. changing releases should get you a little more speed as well. do you know what it is chrono'd at right now? and what is the IBO on the bow?
GT500 27.5/65= 284
GT XT Hunter 7595
Slick Trick 100gr Mags
CBE Tek Hunter with Viper target and 3x lens
Trophy Taker Pronghorn