An idea that mite make knex semi auto. Answered
for the average knex gun, you need to cock it everytime you pull the trigger. couldnt you get a giant fat spring that could act as extra recoil? if you made a gun with a short firing pin and a few bands, with a strong and long spring, dont you think it might be able to be semi auto? If it did work eventually afta about 5 bullets the power would be lost. but still it could work? maybe not sure.