This is my BKO pump I have been working on for some time now.
the sled is made of pvc and steel. and the pump is from a 99 autococker. I tapped a hole in the front valve cap to mount the pump rod and changed the lp reg from the stock one in front of the trigger guard to a kapp lp reg for better control of the ram. the bolt pin is un-modified, the sled keeps it above the ram.
I cut the trigger frame and trigger, because pumps shouldn't have double triggers
Last was the auto trigger. a switch that's activated by the sled keeps the marker from firing until the bolt is closed. IMG_0500.jpg