Here is a quick tutorial on how to replace the safety spring on an AGD Automag frame. I recommend a shorter spring for this style frame since the allen screw takes up some of the space in the hole. Later style sheridan frames also use a shorter spring because they also use an allen screw.
This same procedure works to replace the trigger safety spring in a Sheridan frame but the Sheridan frame lacks a set screw to hold the spring in so you will need a slightly longer spring.
Find Automag parts here:
http://www.baccipaintball.com/parts/semi/airgun-designs-automag-parts.html
Find Sheridan parts here:
http://www.baccipaintball.com/parts/pump-parts/sheridan-pump-parts.html
Find more classic paintball technical and product videos view this playlist:
http://www.youtube.com/playlist?list=PLJC7papTosfU0nPMPDG9ueQ2f3_h973nF