Can anyone tell me how to setup an accurate MSA study for pneumatic torque guns? I cant really check the removal force on screws that were tightened with the gun, because I am dealing with a high degree of creep. Not to mention that removal torque is never the same as applied torque. We use the guns for fastening terminated wire connections. Any help is appreciated.

A torque gun is not a gage, but a process. You should perform a capability study on torque gun using a torque tester/analyzer made specifically for torque guns. I have used Imada brand torque testers with success.