The Automag pump kit hasn't been produced since 1997, according to AGD. However, interest in the pump kit seems to have been picking up recently, with pump kits fetching over $100. The idea behind the pump kit is a simple one - the standard blue bolt bumper is replaced with a wave spring and black bumper. When the trigger is pulled, the bolt flies forward, fires the ball and then the bolt spring pushes the bolt back into place. However, the wave spring keeps the bolt from returning fully (causing what is known as 'bolt stick'). A pump rod lying in a groove in the rail is pushed backward to return the bolt fully to the rear.
Here are the two pages showing the parts and assembly instructions for the pump kit (taken from AGD's site): http://haveblue.org/tech/automag/pump.pdf
The black bumper is 1/16" thick, 3/4" OD and approximately 0.465" ID.
The wave spring is about 0.93" OD, 0.737" ID with a free height of approximately 0.2" and a compressed (solid) height of approximately 0.04". The spring is made of three turns of 0.094" wide, 0.012" thick strip. The closest match from Smalley appears to be the C100-M1, with specs here: http://www.smalley.com/SpringPropert...artNbr=C100-M1
Note that you must have a body with an enlarged sear slot to be able to use the pump kit. According to the above .pdf document, all bodies made after June 1994 have the enlarged sear slot. However, recently made guns appear to have a narrow sear slot - AGD must have returned to the old style slot after discontinuing the pump kit. [Anyone with further information, please contact me] This enlarged sear slot also has a small bevel by one corner where the pump rod passes under.
Kolea Hara provided this photo which shows the difference between a standard body and one with the enlarged slot for the pump rod:
Thanks go to Connieandsimon@sprint.ca
and the Toronto Recreational Paintball Club for these two pictures of the pump kit:
Here's a scan from an issue of APG that shows how the kit gets installed:
Thanks to http://haveblue.org/tech/automag/index.html
fif this information.
Also visit link for CAD's of the pump kit and other Mag parts
If you need a slot milled in your rail for the pump arm both of these guys can do it.
Brad Nestle http://www.bunkerboyz.com/phog/forumdisplay.php?f=13